javap
disassembles Java class files
TLDR
Disassemble class file
$ javap [ClassName]
Show bytecode$ javap -c [ClassName]
Show private members$ javap -p [ClassName]
Verbose output$ javap -v [ClassName]
Disassemble from JAR$ javap -cp [lib.jar] [com.example.Class]
Show line numbers$ javap -l [ClassName]
SYNOPSIS
javap [options] class...
DESCRIPTION
javap disassembles Java class files. It shows method signatures, fields, and optionally bytecode instructions.
The tool is useful for understanding compiled Java code. It can analyze classes without source code access.
PARAMETERS
CLASS
Class name to disassemble.-c
Disassemble bytecode.-p, -private
Show all members.-v, -verbose
Verbose output.-l
Show line number tables.-s
Show internal signatures.-cp PATH
Classpath for classes.--help
Display help information.
CAVEATS
Shows compiled code, not source. Part of JDK. Bytecode knowledge helpful.
HISTORY
javap has been part of the JDK since early versions, providing insight into compiled Java bytecode.