Overview:

javap is a Java class file decomposer that can decompile or view the bytecode generated by the Java compiler to analyze the execution logic inside the code.

Syntax:

Compile the java file into a class file: javac Test.java (Test.java is the name of the java file) and generate the corresponding .class file Test.class

Execute javap operation: javap command line class file name (without .class suffix)

For example: javap -c Test

Command line

- help output javap help information.

-l Output lines and local variable tables.

-b ensures backward compatibility with JDK 1.1 javap.

-public displays only public classes and members.

-protected displays only protected and public classes and members.

-package displays only package, protected and public classes and members. This is the default setting.

-private displays all classes and members.

-J[flag] directly passes the flag to the runtime system.

-s prints the internal type signature.

-c outputs the unparsed code of each method in the class, that is, the instructions that make up the Java bytecode.

-verbose outputs the stack size, the number of locals and args of each method, and the compiled version of the class file

-classpath [path] specifies the path used by javap to find classes. If this option is set, it overrides the default value or the CLASSPATH environment variable. Directories are separated by colons.

- bootclasspath [path] specifies the path used to load the boot class. By default, the bootstrap classes are the classes that implement the core Java platform and are located in jrelibt.jar and jrelibi18n.jar.

-extdirs[dirs] overrides the location of search for installation extensions