Synthesijer is a high-level synthesis tool, which generates VHDL and Verilog HDL code from Java code. Synthesijer also provides a backend to generate VHDL/Verilog HDL, which helps to develop high-level synthesis tools and DSLs.

** Quick start** Prepare a Java program, such as,

/* Test.java */
public class Test{
    public boolean flag;
    private int count = 0;

    public void run(){
        while(true){
            count++;
            if(count == 5000000){
                count = 0;
                flag = !flag;
            }
        }
    }
}

and compile it with Synthesijer.

synthesijer --vhdl --verilog Test.java

You can get Test.vhd and Test.v from Test.java.