JavaValidator.java

Go to the documentation of this file.

package edu.rice.cs.hpc.data.util;

import java.util.Iterator;
import java.util.Map.Entry;
import java.util.Properties;
import java.util.Set;

public class JavaValidator {

    // minimum Java supported
    private final static int JavaMinVersion = 5;
    
    static public void main(String []args) {
        if (isGCJ()) {
            System.out.println("Unsupported JVM: GNU GCJ");
        } else {
            if (isCorrectJavaVersion())
                System.out.println("Valid JVM");
            else
                System.out.println("Invalid JVM: Needs to be higher or equal than " 
                        + JavaMinVersion);
        }
    }
    
    
    /***
     * print all the JVM properties
     */
    static public void printProperties() {
        Properties p = System.getProperties();
        Set<Entry<Object, Object>> set = p.entrySet();
        Iterator<Entry<Object, Object>> iterator = set.iterator();
        
        while(iterator.hasNext()) {
            Entry<Object, Object> entry = iterator.next();
            System.out.println(entry.getKey() + " = " + entry.getValue());
        }
    }
    
    /****
     * check if JVM is from GNU
     * @return
     */
    static public boolean isGCJ() {
        // GNU JVM has "Free Software Foundation" as the vendor
        return getJavaVendor().indexOf("Free")>=0;
    }
    
    /****
     * check if JVM has the correct version
     * @return
     */
    static public boolean isCorrectJavaVersion() {
        String version = getJavaVersion();
        String []items = version.split("\\.");
        int v = Integer.valueOf(items[1]);
        return (v>=JavaMinVersion);
    }
    
    /****
     * retrieve the vendor (Sun, IBM, Free Foundation, ....)
     * @return
     */
    static public String getJavaVendor() {
        return System.getProperty("java.vendor");
    }
    
    /*****
     * retrieve Java version
     * @return
     */
    static public String getJavaVersion() {
        return System.getProperty("java.version");
    }
}