As in document of JDK 1.2, the symcjit compiler is used by default JIT on Windows platforms, and the sunwjit compiler is used by default on Solaris platforms.

However, on Windows NT, the symcjit JIT is set as default for only the user who installed the JDK or JRE with JPI. All other users are set JIT set as None. The following small program can verify it.

//File: PropertiesTest.java
import javax.swing.*;
import java.util.*;

public class PropertiesTest extends JApplet {
        public void init() {
                Properties p = System.getProperties();
                p.list(System.out);
                String jit = p.getProperty("java.compiler");
                JTextField tf = new JTextField(jit);
                getContentPane().add(tf);
        }
}

File: PropertiesTest.html

<EMBED type="application/x-java-applet;version=1.2.2"
 pluginspage="http://java.sun.com/products/plugin/1.2.2/plugin-install.html"
         java_code="PropertiesTest" width=100 height=100>
</EMBED>