jdb 调试工具

1. javac -g hello.java

2. jdb hello

3. stop in hello.main

4. clear/run

5. 

main[1] threads
Group system:
  (java.lang.ref.Reference$ReferenceHandler)0x12c Reference Handler cond. waiting
  (java.lang.ref.Finalizer$FinalizerThread)0x12b  Finalizer         cond. waiting
  (java.lang.Thread)0x12a                         Signal Dispatcher running
Group main:
  (java.lang.Thread)0x1                           main              running (at breakpoint)
main[1]