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Overview Identifying reason for the out of memory error of java applications with larger heap size may be one of the nightmares of a developer, because most of the out of memory situations may not be identified during the testing phase. It may occur only in production after running for a long time. The purpose of this article is to explain the use of Heap analyser tool to identify the memory leakage of larger enterprise java applications, which uses larger size of heaps. Before going to the details we will discuss about following points.          Heap       Garbage Collection           Out of memory What is heap? The space used by the Java Runtime to allocate memory to Objects and JRE Classes is called Heap. The heap space can be configured using the following JVM arguments. o    -Xmx<size> - Setting maximum Java heap size o    -Xms<size> - Setting initial Java heap size The maximum heap size can be configured in a 32 bit JVM is 2GB. If any

In Java 8 we were able to use method implementation in interfaces as default methods. But the private methods were missing in Java 8 when the default method is added.   So now that both default and private methods can exist within an interface. Before we are going to the details we can check the changes came for the interfaces in the previous versions Java 7 In Java 7 we can provide only two things in interfaces ·          Constant variables ·          Abstract methods If we need to use the method implementation, then we should go for the abstract class. Example: public interface SampleInterface_7 {             String CONSTANT_1 = "CONSTANT_1" ;             public void method1(); } Java 8 In Java 8 we can provide following things in interfaces ·          Constant variables ·          Abstract methods ·          Default methods ·          Static methods Default Methods We need to use ‘default’ keyword with the signature