ajdb debugger for .class files produced by ajc (early-access) ajdb -classpath path -Dname=value -help -gui -read file -sourcepath dir -v -verbose :class :gc :jni workingdir dir -Xoption class arguments The command ajdb is used to debug AspectJ and Java programs. In addition to its command line interface, adjb also has a standalone, Swing-based GUI interface. Note: As of the 1.0.3 release, AspectJ supports JSR-45, which provides source-level debugging from many source files per class and non-Java source files. JSR-45 is implemented in the J2SE 1.4 debugger support, so you may be able to use your existing debugger to step through AspectJ source code if both the source and target VM's are running under Java 1.4 or later. However, existing debuggers will display synthetic methods in the stack frame. -classpath path Specify where to find user class files. -Dname=value Define the property name to have the value value. -help Print out ajdb's usage summary. -read file Read this file for initializatoin commands. -sourcepath path Search this directory for source files. -gui -v | -verbose [:class | :gc | :jni] Print out class loading, garbage collection or dynamic library loading information. Defaults to class loading. -workingdir directory Set ajdb's working directory. -Xoption Pass a non-standard option to the VM The AspectJ debugger implements all of jdb's commands. In addition, the command workingdir allow you to set the AspectJ working directory, and the breakpoint command, stop on, has been extended to allow the setting of breakpoint on a source file line. Suppose you want to debug the file spacewar/Ship.java found in the examples directory. At the command line start up the debugger: ajdb The debugger will first look for initialization files in your home or current directory called either ajdb.ini or .ajdbrc and execute the commands contained in them. A useful command to have in this file is the source-path command which tells the debugger where to find source files. For this example, we need to set the source path by: use C:\src To view the file to debug, type list spacewar/Ship.java which generates the following output: 209 void fire() { 210 // firing a shot takes energy 211 if (!expendEnergy(BULLET_ENERGY)) 212 return; 213 214 //create a bullet object so it doesn't hit the ship that's firing it 215 double xV = getXVel() + BULLET_SPEED * (Math.cos(orientation)); 216 double yV = getYVel() + BULLET_SPEED * (Math.sin(orientation)); 217 218 // create the actual bullet 219 new Bullet( 220 getGame(), 221 (getXPos() + ((getSize()/2 + 2) * (Math.cos(orientation))) + xV), 222 (getYPos() + ((getSize()/2 + 2) * (Math.sin(orientation))) + yV), 223 xV, 224 yV); 225 } This is different from jdb because it allows one to view files before the debugger has started. The list command has the following syntax: list list the source containing the location at which we are currently stopped (can only be used with a running VM) list source list the entire file source list source line list source line line of file source list source start-line end-line list the lines from start-line to end-line of file source To set a breakpoint in the method Ship.fire, we would could type stop in spacewar.Ship.fire. The following message appears notifying the user that the breakpoint has been noted but will not be set until the class has been loaded by the VM: Deferring breakpoint spacewar.Ship.fire() It will be set after the class is loaded. To start Spacewar we type run spacewar.Game. When the breakpoint is set, the following message appears: Set deferred breakpoint spacewar.Ship.fire() We are notified that we've hit the breakpoint: Breakpoint hit: thread="Thread-2", spacewar.Ship.fire(), line=174, bci=0 209 void fire() { The prompt changes to present the thread that has broken, and we can view the current stack with the where command, as follows: Thread-2[1] where [1] fire (spacewar\Ship.java:209) [2] run (spacewar\Robot.java:100) [3] run [class java.lang.Thread] Next, to stop on line 216 we type stop on spacewar/Ship.java:216 The following message tells us the breakpoint was set: Set breakpoint Ship.java:216 To continue execution, we type cont and the breakpoint at line 216 is hit Breakpoint hit: thread="Thread-2", spacewar.Ship.fire(), line=216, bci=28 216 double yV = getYVel() + BULLET_SPEED * (Math.sin(orientation)); To view the visible local variables, we type locals and ajdb responds with: Local variables xV = 12.242462584304468 To change the value of the local variable i to 15, we type set xV = 16.1 Changed 'xV' from '12.242462584304468' to '16.1' To see our changes we can print the value of i by the following: print xV Value for printing 'xV' = 12.242462584304468 We can now type exit or quit to leave the debugger, and we receive the following message: The application has exited. The AspectJ debugger is implemented completely in Java and can be called as a Java class. The only interface that should be considered public is the method org.aspectj.tools.debugger.Main.main(String[] args) where args are the standard ajc command line arguments. This means that an alternative way to run the compiler is java org.aspectj.tools.debugger.Main option class arguments You must additionally include tools.jar from your Java developer's kit in your classpath.