Deep insight into your code. IntelliJ IDEA analyzes your code, looking for connections between symbols across all project files and languages. Using this information it provides indepth coding assistance, quick navigation, clever error analysis, and, of course, refactorings.
Features:
Smart completion
Ctrl+Shift+Space gives you a list of the most relevant symbols applicable in the current context. This and other completions are constantly learning from you, moving the members of the most frequently used classes and packages to the top of the suggestions list, so you can select them faster.

Chain completion
Digs a tad deeper than Smart Completion and lists applicable symbols accessible via methods or getters in the current context. Say you're looking for a value of Project and only have the Module module declaration. Press Ctrl+Shift+Space twice to get module.getProject() without any additional effort.

Static members completion
Lets you easily use static methods or constants. Offers a list of symbols matching your input and automatically adds required import statements.

Data flow analysis
When offering completion variants, IntelliJ IDEA analyses data flow to guess the possible runtime symbol type and refines choices based on that intel, automatically adding class casts.