Did you install the source when you installed your JDK? If so, the source is in your JDK directory in a src.zip file. You will need to unzip it and add it to your Eclipse configuration in order to view it. You should be aware that java.util.concurrent.BlockingQueue is an interface, not a class, so I don't think the source will get you far. There are a number of concrete implementations that will probably be far more interesting (see the JDK docs).