mc === > Memory compiler, compiles java files into bytecode and class files in memory. ```bash mc /tmp/Test.java ``` The classloader can be specified with the `-c` option: ```bash mc -c 327a647b /tmp/Test.java ``` The output directory can be specified with the `-d` option: ```bash mc -d /tmp/output /tmp/ClassA.java /tmp/ClassB.java ``` After compiling the `.class` file, you can use the [`redefine`](redefine.md) command to re-define the loaded classes in JVM.