Answer for these kind of questions is Depends.
It's based on your interest & previous experience(background). For example, if you know C or C++, Java is good option. If you know VB then VB.NET/C# is good option.
And why did you choose Ruby & Java? Why didn't you choose other languages such as C#?
It's based on need too. Like in your area what the companies want...
Use Google for comparisons
http://www.google.com/search?q=Ruby+vs+java[
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And first link from search
Ruby vs Java[
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