package com.tets; public class ReferenceCountingGC { public Object instance = null; private static final int _1MB = 1024*1024; private byte[] bigSize = new byte[2 * _1MB]; public static void testGC(){ ReferenceCountingGC obja =new ReferenceCountingGC(); ReferenceCountingGC objb = new ReferenceCountingGC(); obja.instance =objb; objb.instance =obja; obja = null; objb = null; System.gc(); System.out.println("--------------"); } public static void main(String[] args) { testGC(); } } 2017-08-30T22:03:53.744+0800: 1.202: [GC 1.210: [DefNew: 2505K->170K(4928K), 0.0270798 secs] 2505K->2219K(15872K), 0.0353489 secs] [Times: user=0.00 sys=0.00, real=0.04 secs] 2017-08-30T22:03:53.779+0800: 1.238: [Full GC (System) 1.238: [Tenured: 2048K->170K(10944K), 0.0548002 secs] 4267K->170K(15872K), [Perm : 2335K->2335K(12288K)], 0.0554659 secs] [Times: user=0.01 sys=0.00, real=0.06 secs] Heap def new generation total 4992K, used 96K [0x04510000, 0x04a70000, 0x09a60000) eden space 4480K, 2% used [0x04510000, 0x04528028, 0x04970000) from space 512K, 0% used [0x04970000, 0x04970000, 0x049f0000) to space 512K, 0% used [0x049f0000, 0x049f0000, 0x04a70000) tenured generation total 10944K, used 170K [0x09a60000, 0x0a510000, 0x14510000) the space 10944K, 1% used [0x09a60000, 0x09a8abd0, 0x09a8ac00, 0x0a510000) compacting perm gen total 12288K, used 2347K [0x14510000, 0x15110000, 0x18510000) the space 12288K, 19% used [0x14510000, 0x1475af30, 0x1475b000, 0x15110000) No shared spaces configured.
