1. Press Ctrl+Shift+T or, select Navigate > Open Type from the menu bar. The Open Type dialog opens.
2. In the Choose a type field, begin typing an expression to narrow the list of available types, using wildcards as needed. As you type, the list is filtered to display only types that match the current expression.
3. In the Matching Types list, select a type. When there is more than one definition of a type, then select a package in the Qualifier list.
4. Click OK when you are done. An editor opens on the selected type.
Attaching source to a JAR file
Opening an editor for a selected element
Using the Java editor