Core Java

A java.lang.OutOfMemoryError is a subclass of java.lang.VirtualMachineError that is thrown when the Java Virtual Machine is broken or has run out of resources that are necessary to continue the operation of the Java Virtual Machine. Obviously, memory is the exhausted resource for a java.lang.OutOfMemoryError, which is thrown when the Java Virtual Machine cannot allocate...
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Definition Provide an abstract definition for a method or a class and redefine its behavior later or on the fly without changing its structure. Where to use & benefits To make many similar operations template. From many specialized operations to a generalized operation. Refactor common behavior to simplify code. Algorithm related improvement. Need good...
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James Gosling, the creator of the Java programming language, has resigned from Oracle, he announced in a blog entry on Friday Gosling resigned on April 2 and has not yet taken a job elsewhere, he reported. “As to why I left, it’s difficult to answer: just about anything I could say that would be...
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A final class can’t be extended ie., final class may not be subclassed. A final method can’t be overridden when its class is inherited. You can’t change value of a final variable (is a constant).
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JUnit is a simple, open source framework to write and run repeatable tests. It is an instance of the xUnit architecture for unit testing frameworks. JUnit features include: Assertions for testing expected results Test fixtures for sharing common test data Test runners for running tests JUnit was originally written by Erich Gamma and Kent...
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