Use autoboxing/unboxing cautiously

Problem:

public static void main(String args[]) {

Long long1 = Long.valueOf(123L);

Long long2 = new Long("123");

Long long3 = Long.parseLong("123");

long long4 = Long.valueOf(123L);

long long5 = new Long("123");

long long6 = Long.parseLong("123");

System.out.println("long1==long2:"+ (long1==long2));

System.out.println("long1==long3:"+ (long1==long3));

System.out.println("long1==long4:"+ (long1==long4));

System.out.println("long1==long5:"+ (long1==long5));

System.out.println("long1==long6:"+ (long1==long6));

System.out.println("long2==long3:"+ (long2==long3));

System.out.println("long2==long4:"+ (long2==long4));

System.out.println("long2==long5:"+ (long2==long5));

System.out.println("long2==long6:"+ (long2==long6));

System.out.println("long3==long4:"+ (long3==long4));

System.out.println("long3==long5:"+ (long3==long5));

System.out.println("long3==long6:"+ (long3==long6));

System.out.println("long4==long5:"+ (long4==long5));

System.out.println("long4==long6:"+ (long4==long6));

System.out.println("long5==long6:"+ (long5==long6));

}

long1==long2:false
long1==long3:true
long1==long4:true
long1==long5:true
long1==long6:true
long2==long3:false
long2==long4:true
long2==long5:true
long2==long6:true
long3==long4:true
long3==long5:true
long3==long6:true
long4==long5:true
long4==long6:true
long5==long6:true

Solution: If you don't know the origin of the Long object, you may want to check if it is null AND longObject.longValue() for value comparison.