Well, it really depends on what type of game you want to make. Java is an easy language with an extensive API. Because of its simplicity (compared to C/C++), it'll be a lot easier to make games with it. However, it's true that it is rather slow, and making 2D and especially 3D games might lag a bit, depending on how you code it. But if you're making text games, then speed will not be an issue. So, if you're just starting out making games, use Java, but if you want to get into more advanced graphics, C++ will be better. By the way, C++ is the current standard in professional programming (including video games), so if you want to get a job making games, you'd better learn it. Here's an example of making a Space Invaders clone in Java.