A checked exception is any subclass of Exception (or Exception itself), excluding class RuntimeException and its subclasses. Making an exception checked forces client programmers to deal with the possibility that the exception will be thrown. eg, IOException thrown by java.io.FileInputStream’s read() method Unchecked exceptions are RuntimeException and any of its subclasses. Class Error and its subclasses also are unchecked. With an unchecked exception, however, the compiler doesn’t force client programmers either to catch the exception or declare it in a…

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Vector / HashTable are synchronized which means they are thread safe. Cost of thread safe is performance degradation. So if you are sure that you are not dealing with huge number of threads then you should use ArrayList / HashMap.But yes you can stillsynchronize List and Map’s using Collections provided methods :- List OurList = Collections.synchronizedList (OurList); Map OurMap = Collections.synchronizedMap (OurMap);  

An adapter class provides an empty implementation of all methods in an event listener interface. Adapter classes are useful when you want to receive and process only some of the events that are handled by a particular event listener interface. You can define a new class to act listener by extending one of the adapter classes and implementing only those events in which you are interested. For example, the MouseMotionAdapter class has two methods, mouseDragged()and mouseMoved(). The signatures of these…

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