NonStop Server for Java 4.2 Tools Reference

Basic jdb Commands

The following is a list of the basic jdb commands. The Java debugger supports other

commands, which you can list by using the jdb help command.

{help | ?}

Displays the list of recognized commands with a brief description.

run

After starting jdb and setting any necessary breakpoints, you can use this command

to start the execution of the debugged application. This command is available only

when jdb launches the debugged application (as opposed to attaching to an existing

Java VM).

cont

Continues execution of the debugged application after a breakpoint, exception, or

step.

Displays Java objects and primitive values. For variables or fields of primitive types,

the actual value is printed. For objects, a short description is printed. See the dump

command below for getting more information about an object.

Note: To display local variables, the containing class must have been

compiled with the javac -g option.

print supports many simple Java expressions including those with method

invocations, for example:

print MyClass.myStaticField

❍

print myObj.myInstanceField❍

print i + j + k (i, j, k are primitives and either fields or local

variables)

❍

print myObj.myMethod() (if myMethod() returns a non-null)❍

print new java.lang.String("Hello").length()❍

dump

For primitive values, this command is identical to print. For objects, it prints the

current value of each field defined in the object. Static and instance fields are

included.

The dump command supports the same set of expressions as the print command.

threads

List the threads that are currently running. For each thread, its name and current status