checkversion.java

Thinking in Java 是学习JAVA的经典教材

//: com:bruceeckel:tools:CheckVersion.java
// {RunByHand}
// From 'Thinking in Java, 3rd ed.' (c) Bruce Eckel 2002
// www.BruceEckel.com. See copyright notice in CopyRight.txt.
package com.bruceeckel.tools;

public class CheckVersion {
  public static void main(String[] args){
    String version = System.getProperty("java.version");
    char minor = version.charAt(2);
    if (minor < '4')
      throw new RuntimeException("JDK 1.4.0 or higher " +
        "is required to run the examples in this book.");
    System.out.println(
      "JDK version " + version + " found");
  }
} ///:~