Java Language Support

Bugs and Feature Requests: Issue Tracker

This extension provides basic features for the Java programming language. Current editing features include:

• Syntax highlighting and brace matching
• Outlining support for quickly collapsing classes and functions 
• Dropdown bars listing classes, enums, interfaces, fields, and methods within the current document

The latest version of this extension also includes an experimental project system and debugger for Java code. More information about these features is included below.

This extension is not meant to replace a full IDE, but has certainly helped when I wanted to quickly reference a Java source file while working within Visual Studio.

Debugger Support

Current features of the debugger include:

• Support for multiple JVMs
  • Support for the 32- and 64-bit releases of the standard JDK 6 and 7 (HotSpot VM)
  • Support for the 32- and 64-bit releases of JRockit R28.x
• Full support for “Java Runtime Environment” exceptions in the Debug → Exceptions dialog
  • Standard packages and exceptions are shown in the Java Runtime Environment category
  • Users can add their own exceptions by name
  • Users may select which exceptions the debugger should break on at the time they are thrown
  • Unhandled exceptions automatically trigger a breakpoint
  • When an exception is thrown, a message is printed to the output window (similar to the way it’s handled in C# debugging)
• Standard (unconditional) breakpoints
• Stepping in the editor
  • Step Into/Over/Out
  • The Step Over command steps over a statement – with proper support for multiple statements on a single line
• Disassembly window
  • Shows JVM bytecode interleaved with the original source code
  • The Step Over command steps by bytecode instruction instead of by statement
• Support for the Locals, Autos, and Watch windows
• Support for the Immediate window
• Support for pinnable data tips
• Support for the Threads window
• Support for user-friendly representation of collections (lists, maps, arrays, etc.)

Stepping over statements

In our opinion, this is hands-down the coolest feature of our debugger.

We’ve been looking, but so far it seems that no current Java IDE can properly distinguish between multiple statements on a single line. We aim to change that.The image below shows a series of steps in the debugger (the Step Over command was executed exactly one time between each image). As you can see, our debugger follows the logical stepping sequence from the initializer to the condition of the for statement.

Here is an animated image showing a more complete example.

Intuitive display of collections without hiding data

The debugger provides special handling for arrays and classes implementing Collection, Map, and a few other interfaces. To ensure that the debugger doesn’t restrict access to information you need, a special Raw Values property is provided which the user can expand to see the object’s true internal structure. Direct access to the Static Members of classes is provided as well (standard for all classes).

Bytecode disassembly

Curious about what your code is compiling to? The disassembly window fully supports Java bytecode while debugging your program.

Exceptions

The Java debugger extends the Debug → Exceptions window with support for Java Runtime Environment exceptions.

Handling behavior for exceptions may be configured by package or by individual exception type. The following example shows a user configuration requesting the debugger stop immediately when an IllegalArgumentException is thrown.

When an exception is thrown, the debugger first checks to see if the user has requested the debugger stop when the exception is thrown. In this case, we configured the debugger to stop when an IllegalArgumentException is thrown, whether or not a catch statement is available to handle the exception.

If an exception is thrown and no exception handler is available to handle the exception, the debugger stops immediately at the point the unhandled exception is thrown. The user does not need to specially configure the debugger to respond to this error case.

Debugger tool windows

The following image shows the contents of many (but not all) of the currently supported debugger windows in Visual Studio.

Version History

1.2.0 (April 25, 2015)

This should be considered a preview release of the new features of this extension.

• Moved the project to its own GitHub repository
• Support Visual Studio 2015
• Fixed many debugger bugs
• See the release notes for additional information

1.1.0 (March 16, 2014)

This should be considered an early preview release of the new features of this extension.

• Disable the Empty Project template since it isn't working properly
• Stability improvements

1.0.8 (February 20, 2014)

This should be considered an early preview release of the new features of this extension.

• Add Java project system, with support for building and debugging Java code
• Support Visual Studio 2012 and Visual Studio 2013

1.0.6.318 (July 9, 2011)

• Add syntax highlighting for Javadoc comments
• Addressed several potential performance problems

1.0.5.311 (July 8, 2011)

• Original release