JVM

this is a toy Java Virtual Machine implementation

• support Java 8
• support File Read && Write
• support Exception handle

Build

Require

• linux/unix
• C++17
• libzip

cd path/to/JVM
mkdir build
cd build
cmake ..
make

Run

running ./xjava needs boot classpath contains a rt.jar, you need to specify boot classpath with -Xbootclasspath <classpath> if you don't have a $JAVA_HOME env for JDK8

Full Usage

./xjava <options> [classname]

options:

• -help : show help
• -version : show version
• -cp <classpath> : specify user classpath
• -Xbootclasspath <classpath> : specify boot classpath
• -verbose:class : show class loading detail
• -verbose:inst : show instruction excuting detail
• -dump <classname> : show classpy info, equivilent as javap -verbose <classname>

TODO

• support more native methods
• support GC
• support multithreading

Screenshot

show class loading process and instructions excuting:

Updates

• 2020.4.25 add some native methods
• 2022.5.01 support exception handle, file input & output