Java Discussion Boards

Richard MacCutchan8-Jun-22 22:56

8-Jun-22 22:56

Let's start by formatting the code and adding ;line numbers so it is actually readable. You can now clearly see that at the very least you have invalid lines at lines numbers 5 and 22. I assume these are supposed to be comment lines so require a "//" at the beginning. You also have mixed capitalisation on your setters and getters.
So start by fixing those and see what happens.

Java

  1  public class student{
  2      private int ID;
  3      private String Name;
  4  
  5      Student class constructor
  6      student(int id, String name){
  7          this.ID = id;
  8          this.Name = name;
  9      }
 10      public int getid(){
 11          return this.ID;
 12      }
 13      public String Getname(){
 14          return this.Name;
 15      }
 16      public void SETid(int i){
 17          this.ID = i;
 18      }
 19      public void sETNAme(String n){
 20          this.Name=n;
 21      }
 22      method to display data
 23      public void display() {
 24          System.out.println("Student id is: " + id + " "
 25              + "and Student name is: "
 26              + Name;
 27          );
 28          System.out.println();
 29      }
 30  }

Re: solve the error

Sakshi Jain 202226-Jun-22 20:59

Sakshi Jain 2022

26-Jun-22 20:59

You forget to add // on commenting lines that is in line number 5 and 22

Java

public class student{
    private int ID;
    private String Name;

    //Student class constructor
    student(int id, String name){
        this.ID = id;
        this.Name = name;
    }
    public int getid(){
        return this.ID;
    }
    public String Getname(){
        return this.Name;
    }
    public void SETid(int i){
        this.ID = i;
    }
    public void sETNAme(String n){
        this.Name=n;
    }
    // method to display data
    public void display() {
        System.out.println("Student id is: " + id + " "
            + "and Student name is: "
            + Name;
        );
        System.out.println();
    }
}

Re: solve the error

Richard MacCutchan26-Jun-22 21:41

Richard MacCutchan

26-Jun-22 21:41

See my answer of 9th June above.

Re: solve the error

Peter_in_278026-Jun-22 22:19

Peter_in_2780

26-Jun-22 22:19

He already did, when he cut'n'pasted it

Software rusts. Simon Stephenson, ca 1994. So does this signature. me, 2012

Runnable as a new object?

Member 156629325-Jun-22 13:24

Member 15662932

5-Jun-22 13:24

Hello. I'm new to Java -- I want to learn, and am going through HFJ. I know it's an old book, but there are no later editions, so I may be behind the times.

I'm not a professional programmer, but I'm on a few programming forums, and I can't seem to get an answer to a question I have regarding the Runnable interface. I'm in chap 15 of the book re: threading, and I came across this statement in regards to starting a new thread:

public class MyRunnable implements Runnable

Runnable threadJob = new MyRunnable ()

What I don't understand is how can you make a new object with an interface, but use the class MyRunnable. Shouldn't it be MyRunnable thread = new MyRunnable ()?

I'm just confused. Runnable isn't a class, so what's going on?

Re: Runnable as a new object?

Richard MacCutchan5-Jun-22 21:27

Richard MacCutchan

5-Jun-22 21:27

See Runnable (Java Platform SE 7 )[^] and Initial Threads (The Java™ Tutorials > Creating a GUI With Swing > Concurrency in Swing)[^] for full details of this interface.

Re: Runnable as a new object?

Gerry Schmitz6-Jun-22 13:47

Gerry Schmitz

6-Jun-22 13:47

Any class can be "cast" to an interface that it implements; or it can be cast to any object it is "derived" from (e.g. "object").

In your example, a new MyRunnable is created and implicitly "down cast" to Runnable.

The interface acts like a proxy for all (different) classes that implement that interface; allowing only access to the properties / methods identified via the interface.

"Before entering on an understanding, I have meditated for a long time, and have foreseen what might happen. It is not genius which reveals to me suddenly, secretly, what I have to say or to do in a circumstance unexpected by other people; it is reflection, it is meditation." - Napoleon I

Re: Runnable as a new object?

englebart7-Jul-22 16:10

englebart

7-Jul-22 16:10

In C++ terms, a Java interface is a pure abstract class that only has member functions. No fields.

Fields on interfaces are always “constants”. (This is an older Java rule)

It is closer to the COM interface concept.

It could also be called an API contract.

An object can implement multiple interfaces.

This is an easy way to create delayed binding. The thread library was written decades ago, but you can create an Object today that will be usable by this old library as long as you honor the contract defined by the library. For Runnable, you must provide the run() method. The live Thread object will then invoke your run() method when you get your plumbing code correct.

Connect morpho biometric device with jav

Member 156609363-Jun-22 3:10

Member 15660936

3-Jun-22 3:10

connecting morpho biometric device with java in netbeans 8.2 and i want source code

Re: Connect morpho biometric device with jav

Richard MacCutchan3-Jun-22 9:06

Richard MacCutchan

3-Jun-22 9:06

Sorry, this site does not provide code to order.

issue starting my ksql-server

james michael May202225-May-22 13:20

james michael May2022

25-May-22 13:20

hi am having following issue when starting kafta

 confluent local services ksql-server start
The local commands are intended for a single-node development environment only,
NOT for production usage. https://docs.confluent.io/current/cli/index.html

Using CONFLUENT_CURRENT: /tmp/confluent.122197
ZooKeeper is [UP]
Kafka is [UP]
Schema Registry is [UP]
Starting ksqlDB Server
Error: ksqlDB Server failed to start
kafta@kafta-VirtualBox:~$ confluent local services ksql-server log
The local commands are intended for a single-node development environment only,
NOT for production usage. https://docs.confluent.io/current/cli/index.html

OpenJDK 64-Bit Server VM warning: Option UseConcMarkSweepGC was deprecated in version 9.0 and will likely be removed in a future release.
[2022-05-24 11:22:13,133] INFO KsqlConfig values:
        ksql.access.validator.enable = auto
        ksql.authorization.cache.expiry.time.secs = 30
        ksql.authorization.cache.max.entries = 10000
        ksql.cast.strings.preserve.nulls = true
        ksql.connect.basic.auth.credentials.file =
        ksql.connect.basic.auth.credentials.reload = false
        ksql.connect.basic.auth.credentials.source = NONE
        ksql.connect.error.handler = null
        ksql.connect.request.headers.plugin = null
        ksql.connect.url = http://localhost:8083
        ksql.connect.worker.config =
        ksql.create.or.replace.enabled = true
        ksql.error.classifier.regex =
        ksql.extension.dir = ext
        ksql.headers.columns.enabled = true
        ksql.hidden.topics = [_confluent.*, __confluent.*, _schemas, __consumer_offsets, __transaction_state, connect-configs, connect-offsets, connect-status, connect-statuses]
        ksql.insert.into.values.enabled = true
        ksql.internal.topic.min.insync.replicas = 1
        ksql.internal.topic.replicas = 1
        ksql.lambdas.enabled = true
        ksql.metastore.backup.location =
        ksql.metrics.extension = null
        ksql.metrics.tags.custom =
        ksql.nested.error.set.null = true
        ksql.output.topic.name.prefix =
        ksql.persistence.default.format.key = KAFKA
        ksql.persistence.default.format.value = null
        ksql.persistence.wrap.single.values = null
        ksql.persistent.prefix = query_
        ksql.properties.overrides.denylist = []
        ksql.pull.queries.enable = true
        ksql.query.cleanup.shutdown.timeout.ms = 30000
        ksql.query.error.max.queue.size = 10
        ksql.query.persistent.active.limit = 2147483647
        ksql.query.persistent.max.bytes.buffering.total = -1
        ksql.query.pull.consistency.token.enabled = false
        ksql.query.pull.enable.standby.reads = false
        ksql.query.pull.interpreter.enabled = true
        ksql.query.pull.limit.clause.enabled = true
        ksql.query.pull.max.allowed.offset.lag = 9223372036854775807
        ksql.query.pull.max.concurrent.requests = 2147483647
        ksql.query.pull.max.hourly.bandwidth.megabytes = 2147483647
        ksql.query.pull.max.qps = 2147483647
        ksql.query.pull.metrics.enabled = true
        ksql.query.pull.range.scan.enabled = true
        ksql.query.pull.router.thread.pool.size = 50
        ksql.query.pull.stream.enabled = true
        ksql.query.pull.table.scan.enabled = true
        ksql.query.pull.thread.pool.size = 50
        ksql.query.push.v2.alos.enabled = true
        ksql.query.push.v2.catchup.consumer.msg.window = 50
        ksql.query.push.v2.continuation.tokens.enabled = false
        ksql.query.push.v2.enabled = false
        ksql.query.push.v2.interpreter.enabled = true
        ksql.query.push.v2.latest.reset.age.ms = 30000
        ksql.query.push.v2.max.catchup.consumers = 5
        ksql.query.push.v2.max.hourly.bandwidth.megabytes = 2147483647
        ksql.query.push.v2.new.latest.delay.ms = 5000
        ksql.query.push.v2.registry.installed = false
        ksql.query.retry.backoff.initial.ms = 15000
        ksql.query.retry.backoff.max.ms = 900000
        ksql.query.status.running.threshold.seconds = 300
        ksql.query.transient.max.bytes.buffering.total = -1
        ksql.queryanonymizer.cluster_namespace = null
        ksql.queryanonymizer.logs_enabled = true
        ksql.readonly.topics = [_confluent.*, __confluent.*, _schemas, __consumer_offsets, __transaction_state, connect-configs, connect-offsets, connect-status, connect-statuses]
        ksql.rowpartition.rowoffset.enabled = true
        ksql.runtime.feature.shared.enabled = false
        ksql.schema.registry.url = http://localhost:8081
        ksql.security.extension.class = null
        ksql.service.id = default_
        ksql.shared.runtimes.count = 8
        ksql.sink.window.change.log.additional.retention = 1000000
        ksql.source.table.materialization.enabled = true
        ksql.streams.shutdown.timeout.ms = 300000
        ksql.suppress.buffer.size.bytes = -1
        ksql.suppress.enabled = false
        ksql.timestamp.throw.on.invalid = false
        ksql.transient.prefix = transient_
        ksql.udf.collect.metrics = false
        ksql.udf.enable.security.manager = true
        ksql.udfs.enabled = true
        ksql.variable.substitution.enable = true
        metric.reporters = []
        ssl.cipher.suites = null
        ssl.enabled.protocols = [TLSv1.2, TLSv1.3]
        ssl.endpoint.identification.algorithm = https
        ssl.engine.factory.class = null
        ssl.key.password = null
        ssl.keymanager.algorithm = SunX509
        ssl.keystore.certificate.chain = null
        ssl.keystore.key = null
        ssl.keystore.location = null
        ssl.keystore.password = null
        ssl.keystore.type = JKS
        ssl.protocol = TLSv1.3
        ssl.provider = null
        ssl.secure.random.implementation = null
        ssl.trustmanager.algorithm = PKIX
        ssl.truststore.certificates = null
        ssl.truststore.location = null
        ssl.truststore.password = null
        ssl.truststore.type = JKS
 (io.confluent.ksql.util.KsqlConfig:376)
[2022-05-24 11:22:16,956] INFO KsqlRestConfig values:
        access.control.allow.headers = []
        access.control.allow.methods = []
        access.control.allow.origin =
        authentication.method = NONE
        authentication.realm =
        authentication.roles = [*]
        authentication.skip.paths = []
        ksql.advertised.listener = null
        ksql.authentication.plugin.class = null
        ksql.endpoint.logging.ignored.paths.regex =
        ksql.endpoint.logging.log.queries = false
        ksql.healthcheck.interval.ms = 5000
        ksql.heartbeat.check.interval.ms = 200
        ksql.heartbeat.discover.interval.ms = 2000
        ksql.heartbeat.enable = false
        ksql.heartbeat.missed.threshold.ms = 3
        ksql.heartbeat.send.interval.ms = 100
        ksql.heartbeat.thread.pool.size = 3
        ksql.heartbeat.window.ms = 2000
        ksql.idle.connection.timeout.seconds = 86400
        ksql.internal.http2.max.pool.size = 3000
        ksql.internal.listener = null
        ksql.internal.ssl.client.authentication = NONE
        ksql.lag.reporting.enable = false
        ksql.lag.reporting.send.interval.ms = 5000
        ksql.local.commands.location =
        ksql.logging.server.rate.limited.request.paths =
        ksql.logging.server.rate.limited.response.codes =
        ksql.max.push.queries = 100
        ksql.server.command.blocked.threshold.error.ms = 15000
        ksql.server.command.response.timeout.ms = 5000
        ksql.server.error.messages = class io.confluent.ksql.rest.DefaultErrorMessages
        ksql.server.exception.uncaught.handler.enable = false
        ksql.server.install.dir = /opt/confluent
        ksql.server.preconditions = []
        ksql.server.websockets.num.threads = 5
        ksql.ssl.keystore.alias.external =
        ksql.ssl.keystore.alias.internal =
        ksql.verticle.instances = 2
        ksql.worker.pool.size = 100
        listeners = [http://0.0.0.0:8088]
        query.stream.disconnect.check = 1000
        ssl.cipher.suites = []
        ssl.client.auth = false
        ssl.client.authentication = NONE
        ssl.enabled.protocols = [TLSv1.2, TLSv1.3]
        ssl.key.password = [hidden]
        ssl.keystore.location =
        ssl.keystore.password = [hidden]
        ssl.keystore.reload = false
        ssl.keystore.type = JKS
        ssl.keystore.watch.location =
        ssl.truststore.location =
        ssl.truststore.password = [hidden]
        ssl.truststore.type = JKS
 (io.confluent.ksql.rest.server.KsqlRestConfig:376)
[2022-05-24 11:22:17,482] INFO KsqlConfig values:
        ksql.access.validator.enable = auto
        ksql.authorization.cache.expiry.time.secs = 30
        ksql.authorization.cache.max.entries = 10000
        ksql.cast.strings.preserve.nulls = true
        ksql.connect.basic.auth.credentials.file =
        ksql.connect.basic.auth.credentials.reload = false
        ksql.connect.basic.auth.credentials.source = NONE
        ksql.connect.error.handler = null
        ksql.connect.request.headers.plugin = null
        ksql.connect.url = http://localhost:8083
        ksql.connect.worker.config =
        ksql.create.or.replace.enabled = true
        ksql.error.classifier.regex =
        ksql.extension.dir = ext
        ksql.headers.columns.enabled = true
        ksql.hidden.topics = [_confluent.*, __confluent.*, _schemas, __consumer_offsets, __transaction_state, connect-configs, connect-offsets, connect-status, connect-statuses]
        ksql.insert.into.values.enabled = true
        ksql.internal.topic.min.insync.replicas = 1
        ksql.internal.topic.replicas = 1
        ksql.lambdas.enabled = true
        ksql.metastore.backup.location =
        ksql.metrics.extension = null
        ksql.metrics.tags.custom =
        ksql.nested.error.set.null = true
        ksql.output.topic.name.prefix =
        ksql.persistence.default.format.key = KAFKA
        ksql.persistence.default.format.value = null
        ksql.persistence.wrap.single.values = null
        ksql.persistent.prefix = query_
        ksql.properties.overrides.denylist = []
        ksql.pull.queries.enable = true
        ksql.query.cleanup.shutdown.timeout.ms = 30000
        ksql.query.error.max.queue.size = 10
        ksql.query.persistent.active.limit = 2147483647
        ksql.query.persistent.max.bytes.buffering.total = -1
        ksql.query.pull.consistency.token.enabled = false
        ksql.query.pull.enable.standby.reads = false
        ksql.query.pull.interpreter.enabled = true
        ksql.query.pull.limit.clause.enabled = true
        ksql.query.pull.max.allowed.offset.lag = 9223372036854775807
        ksql.query.pull.max.concurrent.requests = 2147483647
        ksql.query.pull.max.hourly.bandwidth.megabytes = 2147483647
        ksql.query.pull.max.qps = 2147483647
        ksql.query.pull.metrics.enabled = true
        ksql.query.pull.range.scan.enabled = true
        ksql.query.pull.router.thread.pool.size = 50
        ksql.query.pull.stream.enabled = true
        ksql.query.pull.table.scan.enabled = true
        ksql.query.pull.thread.pool.size = 50
        ksql.query.push.v2.alos.enabled = true
        ksql.query.push.v2.catchup.consumer.msg.window = 50
        ksql.query.push.v2.continuation.tokens.enabled = false
        ksql.query.push.v2.enabled = false
        ksql.query.push.v2.interpreter.enabled = true
        ksql.query.push.v2.latest.reset.age.ms = 30000
        ksql.query.push.v2.max.catchup.consumers = 5
        ksql.query.push.v2.max.hourly.bandwidth.megabytes = 2147483647
        ksql.query.push.v2.new.latest.delay.ms = 5000
        ksql.query.push.v2.registry.installed = false
        ksql.query.retry.backoff.initial.ms = 15000
        ksql.query.retry.backoff.max.ms = 900000
        ksql.query.status.running.threshold.seconds = 300
        ksql.query.transient.max.bytes.buffering.total = -1
        ksql.queryanonymizer.cluster_namespace = null
        ksql.queryanonymizer.logs_enabled = true
        ksql.readonly.topics = [_confluent.*, __confluent.*, _schemas, __consumer_offsets, __transaction_state, connect-configs, connect-offsets, connect-status, connect-statuses]
        ksql.rowpartition.rowoffset.enabled = true
        ksql.runtime.feature.shared.enabled = false
        ksql.schema.registry.url = http://localhost:8081
        ksql.security.extension.class = null
        ksql.service.id = default_
        ksql.shared.runtimes.count = 8
        ksql.sink.window.change.log.additional.retention = 1000000
        ksql.source.table.materialization.enabled = true
        ksql.streams.shutdown.timeout.ms = 300000
        ksql.suppress.buffer.size.bytes = -1
        ksql.suppress.enabled = false
        ksql.timestamp.throw.on.invalid = false
        ksql.transient.prefix = transient_
        ksql.udf.collect.metrics = false
        ksql.udf.enable.security.manager = true
        ksql.udfs.enabled = true
        ksql.variable.substitution.enable = true
        metric.reporters = []
        ssl.cipher.suites = null
        ssl.enabled.protocols = [TLSv1.2, TLSv1.3]
        ssl.endpoint.identification.algorithm = https
        ssl.engine.factory.class = null
        ssl.key.password = null
        ssl.keymanager.algorithm = SunX509
        ssl.keystore.certificate.chain = null
        ssl.keystore.key = null
        ssl.keystore.location = null
        ssl.keystore.password = null
        ssl.keystore.type = JKS
        ssl.protocol = TLSv1.3
        ssl.provider = null
        ssl.secure.random.implementation = null
        ssl.trustmanager.algorithm = PKIX
        ssl.truststore.certificates = null
        ssl.truststore.location = null
        ssl.truststore.password = null
        ssl.truststore.type = JKS
 (io.confluent.ksql.util.KsqlConfig:376)
[2022-05-24 11:23:06,156] INFO JsonConverterConfig values:
        converter.type = value
        decimal.format = NUMERIC
        schemas.cache.size = 1000
        schemas.enable = false
 (org.apache.kafka.connect.json.JsonConverterConfig:376)
[2022-05-24 11:23:32,941] INFO AdminClientConfig values:
        bootstrap.servers = [localhost:9092]
        client.dns.lookup = use_all_dns_ips
        client.id =
        connections.max.idle.ms = 300000
        default.api.timeout.ms = 60000
        host.resolver.class = class org.apache.kafka.clients.DefaultHostResolver
        metadata.max.age.ms = 300000
        metric.reporters = []
        metrics.num.samples = 2
        metrics.recording.level = INFO
        metrics.sample.window.ms = 30000
        receive.buffer.bytes = 65536
        reconnect.backoff.max.ms = 1000
        reconnect.backoff.ms = 50
        request.timeout.ms = 30000
        retries = 2147483647
        retry.backoff.ms = 100
        sasl.client.callback.handler.class = null
        sasl.jaas.config = null
        sasl.kerberos.kinit.cmd = /usr/bin/kinit
        sasl.kerberos.min.time.before.relogin = 60000
        sasl.kerberos.service.name = null
        sasl.kerberos.ticket.renew.jitter = 0.05
        sasl.kerberos.ticket.renew.window.factor = 0.8
        sasl.login.callback.handler.class = null
        sasl.login.class = null
        sasl.login.connect.timeout.ms = null
        sasl.login.read.timeout.ms = null
        sasl.login.refresh.buffer.seconds = 300
        sasl.login.refresh.min.period.seconds = 60
        sasl.login.refresh.window.factor = 0.8
        sasl.login.refresh.window.jitter = 0.05
        sasl.login.retry.backoff.max.ms = 10000
        sasl.login.retry.backoff.ms = 100
        sasl.mechanism = GSSAPI
        sasl.oauthbearer.clock.skew.seconds = 30
        sasl.oauthbearer.expected.audience = null
        sasl.oauthbearer.expected.issuer = null
        sasl.oauthbearer.jwks.endpoint.refresh.ms = 3600000
        sasl.oauthbearer.jwks.endpoint.retry.backoff.max.ms = 10000
        sasl.oauthbearer.jwks.endpoint.retry.backoff.ms = 100
        sasl.oauthbearer.jwks.endpoint.url = null
        sasl.oauthbearer.scope.claim.name = scope
        sasl.oauthbearer.sub.claim.name = sub
        sasl.oauthbearer.token.endpoint.url = null
        security.protocol = PLAINTEXT
        security.providers = null
        send.buffer.bytes = 131072
        socket.connection.setup.timeout.max.ms = 30000
        socket.connection.setup.timeout.ms = 10000
        ssl.cipher.suites = null
        ssl.enabled.protocols = [TLSv1.2, TLSv1.3]
        ssl.endpoint.identification.algorithm = https
        ssl.engine.factory.class = null
        ssl.key.password = null
        ssl.keymanager.algorithm = SunX509
        ssl.keystore.certificate.chain = null
        ssl.keystore.key = null
        ssl.keystore.location = null
        ssl.keystore.password = null
        ssl.keystore.type = JKS
        ssl.protocol = TLSv1.3
        ssl.provider = null
        ssl.secure.random.implementation = null
        ssl.trustmanager.algorithm = PKIX
        ssl.truststore.certificates = null
        ssl.truststore.location = null
        ssl.truststore.password = null
        ssl.truststore.type = JKS
 (org.apache.kafka.clients.admin.AdminClientConfig:376)
[2022-05-24 11:23:35,925] WARN The configuration 'metrics.context.resource.version' was supplied but isn't a known config. (org.apache.kafka.clients.admin.AdminClientConfig:384)
[2022-05-24 11:23:35,926] WARN The configuration 'metrics.context.resource.commit.id' was supplied but isn't a known config. (org.apache.kafka.clients.admin.AdminClientConfig:384)
[2022-05-24 11:23:36,968] INFO [AdminClient clientId=adminclient-1] Node -1 disconnected. (org.apache.kafka.clients.NetworkClient:1047)
[2022-05-24 11:23:37,068] WARN [AdminClient clientId=adminclient-1] Connection to node -1 (localhost/127.0.0.1:9092) could not be established. Broker may not be available. (org.apache.kafka.clients.NetworkClient:870)
[2022-05-24 11:23:37,173] INFO [AdminClient clientId=adminclient-1] Node -1 disconnected. (org.apache.kafka.clients.NetworkClient:1047)
[2022-05-24 11:23:37,173] WARN [AdminClient clientId=adminclient-1] Connection to node -1 (localhost/127.0.0.1:9092) could not be established. Broker may not be available. (org.apache.kafka.clients.NetworkClient:870)
[2022-05-24 11:23:37,374] INFO [AdminClient clientId=adminclient-1] Node -1 disconnected. (org.apache.kafka.clients.NetworkClient:1047)
[2022-05-24 11:23:37,374] WARN [AdminClient clientId=adminclient-1] Connection to node -1 (localhost/127.0.0.1:9092) could not be established. Broker may not be available. (org.apache.kafka.clients.NetworkClient:870)
[2022-05-24 11:23:37,686] INFO [AdminClient clientId=adminclient-1] Node -1 disconnected. (org.apache.kafka.clients.NetworkClient:1047)
[2022-05-24 11:23:37,686] WARN [AdminClient clientId=adminclient-1] Connection to node -1 (localhost/127.0.0.1:9092) could not be established. Broker may not be available. (org.apache.kafka.clients.NetworkClient:870)
[2022-05-24 11:23:38,202] INFO [AdminClient clientId=adminclient-1] Node -1 disconnected. (org.apache.kafka.clients.NetworkClient:1047)
[2022-05-24 11:23:38,206] WARN [AdminClient clientId=adminclient-1] Connection to node -1 (localhost/127.0.0.1:9092) could not be established. Broker may not be available. (org.apache.kafka.clients.NetworkClient:870)
[2022-05-24 11:23:39,129] INFO [AdminClient clientId=adminclient-1] Node -1 disconnected. (org.apache.kafka.clients.NetworkClient:1047)
[2022-05-24 11:23:39,436] WARN [AdminClient clientId=adminclient-1] Connection to node -1 (localhost/127.0.0.1:9092) could not be established. Broker may not be available. (org.apache.kafka.clients.NetworkClient:870)
[2022-05-24 11:23:40,991] INFO [AdminClient clientId=adminclient-1] Node -1 disconnected. (org.apache.kafka.clients.NetworkClient:1047)
[2022-05-24 11:23:40,991] WARN [AdminClient clientId=adminclient-1] Connection to node -1 (localhost/127.0.0.1:9092) could not be established. Broker may not be available. (org.apache.kafka.clients.NetworkClient:870)
[2022-05-24 11:23:42,020] INFO [AdminClient clientId=adminclient-1] Node -1 disconnected. (org.apache.kafka.clients.NetworkClient:1047)
[2022-05-24 11:23:42,024] WARN [AdminClient clientId=adminclient-1] Connection to node -1 (localhost/127.0.0.1:9092) could not be established. Broker may not be available. (org.apache.kafka.clients.NetworkClient:870)
[2022-05-24 11:23:43,064] INFO [AdminClient clientId=adminclient-1] Node -1 disconnected. (org.apache.kafka.clients.NetworkClient:1047)
[2022-05-24 11:23:43,064] WARN [AdminClient clientId=adminclient-1] Connection to node -1 (localhost/127.0.0.1:9092) could not be established. Broker may not be available. (org.apache.kafka.clients.NetworkClient:870)
[2022-05-24 11:23:43,996] INFO [AdminClient clientId=adminclient-1] Node -1 disconnected. (org.apache.kafka.clients.NetworkClient:1047)
[2022-05-24 11:23:43,997] WARN [AdminClient clientId=adminclient-1] Connection to node -1 (localhost/127.0.0.1:9092) could not be established. Broker may not be available. (org.apache.kafka.clients.NetworkClient:870)
[2022-05-24 11:23:45,241] INFO [AdminClient clientId=adminclient-1] Node -1 disconnected. (org.apache.kafka.clients.NetworkClient:1047)
[2022-05-24 11:23:45,242] WARN [AdminClient clientId=adminclient-1] Connection to node -1 (localhost/127.0.0.1:9092) could not be established. Broker may not be available. (org.apache.kafka.clients.NetworkClient:870)
[2022-05-24 11:23:46,174] INFO [AdminClient clientId=adminclient-1] Node -1 disconnected. (org.apache.kafka.clients.NetworkClient:1047)
[2022-05-24 11:23:46,175] WARN [AdminClient clientId=adminclient-1] Connection to node -1 (localhost/127.0.0.1:9092) could not be established. Broker may not be available. (org.apache.kafka.clients.NetworkClient:870)
[2022-05-24 11:23:47,101] INFO [AdminClient clientId=adminclient-1] Node -1 disconnected. (org.apache.kafka.clients.NetworkClient:1047)
[2022-05-24 11:23:47,102] WARN [AdminClient clientId=adminclient-1] Connection to node -1 (localhost/127.0.0.1:9092) could not be established. Broker may not be available. (org.apache.kafka.clients.NetworkClient:870)
[2022-05-24 11:23:48,342] INFO [AdminClient clientId=adminclient-1] Node -1 disconnected. (org.apache.kafka.clients.NetworkClient:1047)
[2022-05-24 11:23:48,343] WARN [AdminClient clientId=adminclient-1] Connection to node -1 (localhost/127.0.0.1:9092) could not be established. Broker may not be available. (org.apache.kafka.clients.NetworkClient:870)
[2022-05-24 11:23:49,569] INFO [AdminClient clientId=adminclient-1] Node -1 disconnected. (org.apache.kafka.clients.NetworkClient:1047)
[2022-05-24 11:23:49,569] WARN [AdminClient clientId=adminclient-1] Connection to node -1 (localhost/127.0.0.1:9092) could not be established. Broker may not be available. (org.apache.kafka.clients.NetworkClient:870)
[2022-05-24 11:23:50,794] INFO [AdminClient clientId=adminclient-1] Node -1 disconnected. (org.apache.kafka.clients.NetworkClient:1047)
[2022-05-24 11:23:50,899] WARN [AdminClient clientId=adminclient-1] Connection to node -1 (localhost/127.0.0.1:9092) could not be established. Broker may not be available. (org.apache.kafka.clients.NetworkClient:870)
[2022-05-24 11:23:51,808] INFO [AdminClient clientId=adminclient-1] Node -1 disconnected. (org.apache.kafka.clients.NetworkClient:1047)
[2022-05-24 11:23:51,809] WARN [AdminClient clientId=adminclient-1] Connection to node -1 (localhost/127.0.0.1:9092) could not be established. Broker may not be available. (org.apache.kafka.clients.NetworkClient:870)
[2022-05-24 11:23:52,740] INFO [AdminClient clientId=adminclient-1] Node -1 disconnected. (org.apache.kafka.clients.NetworkClient:1047)
[2022-05-24 11:23:52,740] WARN [AdminClient clientId=adminclient-1] Connection to node -1 (localhost/127.0.0.1:9092) could not be established. Broker may not be available. (org.apache.kafka.clients.NetworkClient:870)
[2022-05-24 11:23:53,871] INFO [AdminClient clientId=adminclient-1] Node -1 disconnected. (org.apache.kafka.clients.NetworkClient:1047)
[2022-05-24 11:23:53,872] WARN [AdminClient clientId=adminclient-1] Connection to node -1 (localhost/127.0.0.1:9092) could not be established. Broker may not be available. (org.apache.kafka.clients.NetworkClient:870)
[2022-05-24 11:23:54,900] INFO [AdminClient clientId=adminclient-1] Node -1 disconnected. (org.apache.kafka.clients.NetworkClient:1047)
[2022-05-24 11:23:54,901] WARN [AdminClient clientId=adminclient-1] Connection to node -1 (localhost/127.0.0.1:9092) could not be established. Broker may not be available. (org.apache.kafka.clients.NetworkClient:870)
[2022-05-24 11:23:55,910] INFO [AdminClient clientId=adminclient-1] Node -1 disconnected. (org.apache.kafka.clients.NetworkClient:1047)
[2022-05-24 11:23:55,911] WARN [AdminClient clientId=adminclient-1] Connection to node -1 (localhost/127.0.0.1:9092) could not be established. Broker may not be available. (org.apache.kafka.clients.NetworkClient:870)
[2022-05-24 11:23:57,019] INFO [AdminClient clientId=adminclient-1] Node -1 disconnected. (org.apache.kafka.clients.NetworkClient:1047)
[2022-05-24 11:23:57,019] WARN [AdminClient clientId=adminclient-1] Connection to node -1 (localhost/127.0.0.1:9092) could not be established. Broker may not be available. (org.apache.kafka.clients.NetworkClient:870)
[2022-05-24 11:23:58,045] INFO [AdminClient clientId=adminclient-1] Node -1 disconnected. (org.apache.kafka.clients.NetworkClient:1047)
[2022-05-24 11:23:58,046] WARN [AdminClient clientId=adminclient-1] Connection to node -1 (localhost/127.0.0.1:9092) could not be established. Broker may not be available. (org.apache.kafka.clients.NetworkClient:870)
[2022-05-24 11:23:59,282] INFO [AdminClient clientId=adminclient-1] Node -1 disconnected. (org.apache.kafka.clients.NetworkClient:1047)
[2022-05-24 11:23:59,282] WARN [AdminClient clientId=adminclient-1] Connection to node -1 (localhost/127.0.0.1:9092) could not be established. Broker may not be available. (org.apache.kafka.clients.NetworkClient:870)
[2022-05-24 11:24:00,308] INFO [AdminClient clientId=adminclient-1] Node -1 disconnected. (org.apache.kafka.clients.NetworkClient:1047)
[2022-05-24 11:24:00,309] WARN [AdminClient clientId=adminclient-1] Connection to node -1 (localhost/127.0.0.1:9092) could not be established. Broker may not be available. (org.apache.kafka.clients.NetworkClient:870)
[2022-05-24 11:24:01,431] INFO [AdminClient clientId=adminclient-1] Node -1 disconnected. (org.apache.kafka.clients.NetworkClient:1047)
[2022-05-24 11:24:01,431] WARN [AdminClient clientId=adminclient-1] Connection to node -1 (localhost/127.0.0.1:9092) could not be established. Broker may not be available. (org.apache.kafka.clients.NetworkClient:870)
[2022-05-24 11:24:02,758] INFO [AdminClient clientId=adminclient-1] Node -1 disconnected. (org.apache.kafka.clients.NetworkClient:1047)
[2022-05-24 11:24:02,758] WARN [AdminClient clientId=adminclient-1] Connection to node -1 (localhost/127.0.0.1:9092) could not be established. Broker may not be available. (org.apache.kafka.clients.NetworkClient:870)
[2022-05-24 11:24:03,675] INFO [AdminClient clientId=adminclient-1] Node -1 disconnected. (org.apache.kafka.clients.NetworkClient:1047)
[2022-05-24 11:24:03,676] WARN [AdminClient clientId=adminclient-1] Connection to node -1 (localhost/127.0.0.1:9092) could not be established. Broker may not be available. (org.apache.kafka.clients.NetworkClient:870)
[2022-05-24 11:24:04,894] INFO [AdminClient clientId=adminclient-1] Node -1 disconnected. (org.apache.kafka.clients.NetworkClient:1047)
[2022-05-24 11:24:04,894] WARN [AdminClient clientId=adminclient-1] Connection to node -1 (localhost/127.0.0.1:9092) could not be established. Broker may not be available. (org.apache.kafka.clients.NetworkClient:870)
[2022-05-24 11:24:06,109] INFO [AdminClient clientId=adminclient-1] Node -1 disconnected. (org.apache.kafka.clients.NetworkClient:1047)
[2022-05-24 11:24:06,114] WARN [AdminClient clientId=adminclient-1] Connection to node -1 (localhost/127.0.0.1:9092) could not be established. Broker may not be available. (org.apache.kafka.clients.NetworkClient:870)
[2022-05-24 11:24:06,140] INFO [AdminClient clientId=adminclient-1] Metadata update failed (org.apache.kafka.clients.admin.internals.AdminMetadataManager:235)
org.apache.kafka.common.errors.TimeoutException: Timed out waiting for a node assignment. Call: fetchMetadata
[2022-05-24 11:24:06,143] ERROR Failed to start KSQL (io.confluent.ksql.rest.server.KsqlServerMain:70)
java.lang.RuntimeException: Failed to get Kafka cluster information
        at io.confluent.ksql.services.KafkaClusterUtil.getKafkaClusterId(KafkaClusterUtil.java:107)
        at io.confluent.ksql.rest.server.KsqlRestApplication.buildApplication(KsqlRestApplication.java:645)
        at io.confluent.ksql.rest.server.KsqlServerMain.createExecutable(KsqlServerMain.java:162)
        at io.confluent.ksql.rest.server.KsqlServerMain.main(KsqlServerMain.java:63)
Caused by: java.util.concurrent.TimeoutException
        at java.base/java.util.concurrent.CompletableFuture.timedGet(CompletableFuture.java:1886)
        at java.base/java.util.concurrent.CompletableFuture.get(CompletableFuture.java:2021)
        at org.apache.kafka.common.internals.KafkaFutureImpl.get(KafkaFutureImpl.java:180)
        at io.confluent.ksql.services.KafkaClusterUtil.getKafkaClusterId(KafkaClusterUtil.java:105)
        ... 3 more
kafta@kafta-VirtualBox:~$

Re: issue starting my ksql-server

Richard MacCutchan25-May-22 22:03

Richard MacCutchan

25-May-22 22:03

This has nothing to do with Java programming. The error messages are clearly identifying issues with the third party product. You should go to the KafkaSQL website for help.

Hash Table implementation

Member 156289598-May-22 18:52

Member 15628959

8-May-22 18:52

Hash tables provide a mechanism by which you can create indexed tables in which the index is a value other than a string. Implement and test an integer key Open Address Hash table. Implement the following interface. • String get(int k); • void put(int k, String v); • bool contains(int k); • void delete(int k); • void printHash(); You must provide an interactive or command-line test application for the hash table. Make the hash table 31 entries, and make sure at least one collision occurs in your data input. You must delete some data from your table to demonstrate deletion. (100 points)

Notable to get output. Could you please anyone help me on this

Re: Hash Table implementation

Richard Deeming8-May-22 21:27

Richard Deeming

8-May-22 21:27

Nobody is going to do your homework for you. If you don't know where to start, talk to your teacher.

"These people looked deep within my soul and assigned me a number based on the order in which I joined."
- Homer

Re: Hash Table implementation

Richard MacCutchan8-May-22 21:43

Richard MacCutchan

8-May-22 21:43

See Java Tutorials Learning Paths[^]

Hi guys my code is not compiling as its showing cannot find symbol please help

Member 1561125322-Apr-22 4:48

Member 15611253

22-Apr-22 4:48

package classes;

import java.io.File;
import java.io.FileNotFoundException;
import java.util.ArrayList;
import java.util.Scanner;

public class Inventory {

    private ArrayList <Item> listItems;

    public Inventory() {
        listItems = new ArrayList<Item>();
        readInventory();
    }

    public void showInventory() {
        for (int i = 0; i < listItems.size(); i++) {
            System.out.println(i + 1 + ". " + listItems.get(i).getName());
        }
    }

    public Item getItem(int index) {
        if (index <= listItems.size()) {
            return listItems.get(index);
        }
        return null;
    }

    public int inventorySize() {
        return listItems.size();
    }

    private void readInventory() {
        try {
            File myObj = new File("data/inventory.txt");
            Scanner myReader = new Scanner(myObj);
            while (myReader.hasNextLine()) {
                String line = myReader.nextLine();
                String[] data = line.split(",");
                String name = data[0];
                double price = Double.parseDouble(data[1]);
                Item item = new Item(name, price);
                listItems.add(item);
            }
            myReader.close();
        } catch (FileNotFoundException e) {
            System.out.println("An error occurred. The inventory file not found.");

        }
    }

}

Re: Hi guys my code is not compiling as its showing cannot find symbol please help

Dave Kreskowiak22-Apr-22 4:53

Dave Kreskowiak

22-Apr-22 4:53

Since you didn't supply the exact error message and the line it occurs on, I'm going to take a wild ass guess and say that you don't have a class called Item defined anywhere.

Asking questions is a skill
CodeProject Forum Guidelines
Google: C# How to debug code
Seriously, go read these articles.

Dave Kreskowiak

Re: Hi guys my code is not compiling as its showing cannot find symbol please help

zemiak1231-May-22 13:06

zemiak123

1-May-22 13:06

Item class can be like

class Item {
  String name;
  double price;

  Item( String name, double price) {
    this.name=name; this.price=price;
  }
  String getName() { return name; }
}

Development of Wiki functionality in JSF project

Dev Learning22-Apr-22 2:25

Dev Learning

22-Apr-22 2:25

I am developing a web application with JSF and Primefaces and I would like to integrate a simple wiki functionality which consists only of the creation and visualization of content such as course, definition of an object ... etc.

I know that there are open sources for wikis such as JSPWiki, DevWiki, but is there an other simple alternatives such as a dependency that can be integrated into project ?

Thank you for your reply

Prateek Bajpai10-Apr-22 4:49

Prateek Bajpai

10-Apr-22 4:49

This is Parteek Bajpai, BE COMP student of Bharati Vidyapeeth College of Engineering, Lavale, Pune. I am here to post my problem so that anyone can resolve my problem.

import java.util.ArrayList;
import java.util.List;
public class Solution {
public static int first(List<integer> arr, int low, int high, int x, int n){
if(high >= low){
int mid = low+(high+low)/2;

if(mid == 0 || x>arr.get(mid-1) && arr.get(mid) == x){
return mid;
}
if(x > arr.get(mid)){
return first(arr, (mid+1), high, x, n);
}
else{
return first(arr, low, (mid-1), x, n);
}
}
return -1;
}
public static List<integer> relativeSorting(List<integer> arr, List<integer> brr, int n, int m) {
// Write your code here
List<integer> temp = new ArrayList<integer>(m);
List<integer> visited = new ArrayList<integer>(m);
for(int i=0; i

Richard MacCutchan10-Apr-22 5:53

Richard MacCutchan

10-Apr-22 5:53

Apart from the fact that the posted code is incomplete, you have not given any information about what your problem is.

HOW TO USE JTABLE TO DISPLAY ALL RECORDS DATA FROM DATABASE USING JDBC

Member 1558267928-Mar-22 21:48

Member 15582679

28-Mar-22 21:48

Hi,

I am new for java. Can anyone share with me how to read the data from database using JDBC and load the data into JTable?

Because i saw most of the sample for JTable is using hard coded data and show the data in JTable or reading the data from database with fix no of row and column or using DefaultTableModal.

May i know that besides using tablemodal, is there any way to display all data to JTable?

I am looking for something the no of row is not fix, it will depend on the no of records in the database to load into it.

Thank You.

Re: HOW TO USE JTABLE TO DISPLAY ALL RECORDS DATA FROM DATABASE USING JDBC

Richard MacCutchan29-Mar-22 1:31

Richard MacCutchan

29-Mar-22 1:31

Take a look at How to Use Tables (The Java™ Tutorials)[^] and Trail: JDBC Database Access (The Java™ Tutorials)[^]. But if you are new then I would suggest something less advanced to start with.

Re: HOW TO USE JTABLE TO DISPLAY ALL RECORDS DATA FROM DATABASE USING JDBC

Member 155826795-Apr-22 21:49

Member 15582679

5-Apr-22 21:49

Hi Richard,

Thank You.

WhiteSpace Character

Sudhanshu_India5-Mar-22 23:26

Sudhanshu_India

5-Mar-22 23:26

public class JavaCharacterisWhitespaceExample_1 {
public static void main(String[] args) {
// Initialize three codepoints: cp1, cp2 and cp3
int cp1 = 49;
int cp2 = 121;
int cp3 = 234;
// Check whether the codepoints are whitespaces or not.
boolean check1 = Character.isWhitespace(cp1);
boolean check2 = Character.isWhitespace(cp2);
boolean check3 = Character.isWhitespace(cp3);
// Print the result.
if(check1){
System.out.print("The codepoint \'"+cp1+"\' is a whitespace character.\n");
}
else{
System.out.print("The codePoint \'"+cp1+"\' is not a whitespace character.\n");
}

if(check2){
System.out.print("The codepoint \'"+cp2+"\' is a whitespace character.\n");
}
else{
System.out.print("The codePoint \'"+cp2+"\' is not a whitespace character.\n");
}

if(check3){
System.out.print("The codepoint \'"+cp3+"\' is a whitespace character.\n");
}
else{
System.out.print("The codePoint \'"+cp3+"\' is not a whitespace character.\n");
}
}
}

Output:
-----------

The codePoint '49' is not a whitespace character.
The codePoint '121' is not a whitespace character.
The codePoint '234' is not a whitespace character.
--------------------------------------------------------------------------------------------------------

public class JavaCharacterisWhitespaceExample_2 {
public static void main(String[] args) {
// Initialize three codepoints: cp1, cp2 and cp3
int cp1 = 9;
int cp2 = 10;
int cp3 = 13;
// Check whether the codepoints are whitespaces or not.
boolean check1 = Character.isWhitespace(cp1);
boolean check2 = Character.isWhitespace(cp2);
boolean check3 = Character.isWhitespace(cp3);
// Print the result.
if(check1){
System.out.print("The codepoint \'"+cp1+"\' is a whitespace character.\n");
}
else{
System.out.print("The codePoint \'"+cp1+"\' is not a whitespace character.\n");
}

if(check2){
System.out.print("The codepoint \'"+cp2+"\' is a whitespace character.\n");
}
else{
System.out.print("The codePoint \'"+cp2+"\' is not a whitespace character.\n");
}

if(check3){
System.out.print("The codepoint \'"+cp3+"\' is a whitespace character.\n");
}
else{
System.out.print("The codePoint \'"+cp3+"\' is not a whitespace character.\n");
}
}
}

Output:
-----------

The codepoint '9' is a whitespace character.
The codepoint '10' is a whitespace character.
The codepoint '13' is a whitespace character.

My Question is why 9,10 & 13 are whitespace characters while 49, 121,234 are not, though all of them are number?

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