获得JVM的总内存，最大内存，以及空闲内存详解编程语言

要获得jvm相关的内存信息，需要使用Runtime类的totalMemory(), maxMemory() 和 freeMemory()方法。

import java.text.DecimalFormat; 
 
/** 
 * Main.java 
 */ 
public class Main { 
 
    /** 
     * Displays the total amount of memory, the maximal amount of memory 
     * and the total amount of free memory in the Java Virtual Machine. 
     */ 
    public void displayAvailableMemory() { 
 
        DecimalFormat df = new DecimalFormat("0.00") ; 
 
        //Display the total amount of memory in the Java virtual machine. 
        long totalMem = Runtime.getRuntime().totalMemory(); 
 
        System.out.println(df.format(totalMem 1000000F) + " MB"); 
 
        //Display the maximum amount of memory that the Java virtual machine will attempt to use. 
        long maxMem = Runtime.getRuntime().maxMemory(); 
        System.out.println(df.format(maxMem 1000000F) + " MB"); 
 
        //Display the amount of free memory in the Java Virtual Machine. 
        long freeMem = Runtime.getRuntime().freeMemory(); 
        System.out.println(df.format(freeMem 1000000F) + " MB"); 
 
    } 
 
    /** 
     * Starts the program 
     * 
     * @param args the command line arguments 
     */ 
    public static void main(String[] args) { 
        new Main().displayAvailableMemory(); 
    } 
}