ntrp/jdb.vim

A jdb wrapper for VIM as a plugin

A JDB plugin for VIM

With the plugin, you could set breakpoint in some Java file with VIM, attach to some running JVM with JDWP enabled, then step through your code.

The plugin depends on channel feature from VIM 8.0, so to use this plugin, you must have VIM over 8.0.

Steps to use

1. Launch your java program with JDWP enabled, such as

   java -agentlib:jdwp=transport=dt_socket,server=y,suspend=y,address=6789 Sample

   MAVEN_OPTS="-agentlib:jdwp=transport=dt_socket,server=y,address=6789,server=y,suspend=n" mvn spring-boot:run

2. Open your java source file with VIM

3. <F10> to set breakpoint at current line

4. <F5> to attach to the running JVM, if you're using different port, change it with below command

   let g:jdbPort="6799"

   After you attached to the running JVM, you'll see a console window below current window. You could input any jdb command in console window, escape to normal mode to press enter to execute it.

5. <F3> to step through your code now.

Debugging keys

• <F2> to step into.
• <F4> to step out.
• <F5> to continue.
• <F6> to quit.
• Visual select a word or expression, then E to print its value or eval it.

Breakpoint in nested class

For explicitly declared nested class, you could set breakpoint just as in normal class. But for some anonymous nested class, you need follow below steps.

In the console window, input

class com.your.org.ClassWithNestedClass

escape to normal mode, press enter, it will list all nested anonymous classes, such as

main[1] Class: com.your.org.ClassWithNestedClass
extends: android.webkit.WebView
nested: com.your.org.ClassWithNestedClass$1
nested: com.your.org.ClassWithNestedClass$2
nested: com.your.org.ClassWithNestedClass$3
nested: com.your.org.ClassWithNestedClass$4
nested: com.your.org.ClassWithNestedClass$5

check each nested class with command class com.your.org.<nestedClassName>, such as

class com.your.org.ClassWithNestedClass$4

to get the exact one you need.

Then use command

stop in com.your.org.ClassWithNestedClass$4.<MethodNameInThisNestedClass>