see code verification
/** * Integer cache mechanism * The following caches are only useful for autoboxing. new objects are useless */ public class IntegerTypeCache { public static void main(String[] args) { /** * When the running log is greater than 127, the reference of autobox is judged to be false */ for (int i = 0; i < 200; i++) { /** * Integer Cache test * * The cache defaults to -128 to 127, the range may be modified by -XX:AutoBoxCacheMax=size */ Integer integer1 = new Integer(i); Integer integer2 = new Integer(i); Integer integer3 = i; Integer integer4 = i; boolean result1 = integer1 == integer2; boolean result2 = integer3 == integer4; System.out.println("integer1 " + integer1 + " = integer2 " + integer2 + " result is " + result1); System.out.println("integer3 " + integer3 + " = integer4 " + integer4 + " result is " + result2); /** * Long Cache test * The cache range is -128 to 127 */ Long long1 = new Long(i); Long long2 = new Long(i); Integer long3 = i; Integer long4 = i; boolean result3 = long1 == long2; boolean result4 = long3 == long4; System.out.println("long1 " + long1 + " = long2 " + long2 + " result is " + result3); System.out.println("long3 " + long3 + " = long4 " + long4 + " result is " + result4); /** *Short Cache test * The cache range is -128 to 127 */ Short short1 = new Short((short) i); Short short2 = new Short((short) i); Short short3 = (short) i; Short short4 = (short) i; boolean result5 = short1 == short2; boolean result6 = short3 == short4; System.out.println("short1 " + short1 + " = short2 " + short2 + " result is " + result5); System.out.println("short3 " + short3 + " = short4 " + short4 + " result is " + result6); System.out.println(); } /** * Character cache size is unicode 0-127 */ Character character1 = new Character('1'); //unicode 49 Character character2 = '1'; Character character3 = '1'; System.out.println("character1 == character2 " + (character1 == character2));//false System.out.println("character3 == character4 " + (character2 == character3));//true Character character4 = new Character('大');//unicode>127 Character character7 = new Character('大'); Character character5 = '大'; Character character6 = '大'; System.out.println("character4 == character5 " + (character4 == character5));//false System.out.println("character5 == character6 " + (character5 == character6));//false System.out.println("character4 == character7 " + (character4 == character7));//false /** * Byte cache size is -128 to 127 * autobox's reference comparisons are all true */ for (byte i = Byte.MIN_VALUE; i < Byte.MAX_VALUE; i++) { Byte byte1 = new Byte(i); Byte byte2 = new Byte(i); Byte byte3 = i; Byte byte4 = i; System.out.println("byte1 " + byte1 + " == byte2 " + byte2 + " is " + (byte1 == byte2));//false System.out.println("byte3 " + byte3 + " == byte4 " + byte4 + " is " + (byte3 == byte4));//true System.out.println(); } } }