Exception Chaining in Java

Exception chaining in java allows us to relate one exception to another exception. An application often responds to an exception by throwing another exception. In effect, the first exception causes the second exception. It can be very helpful to know when one

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Difference between Throw and Throws in Exception Handling

We have seen examples of Throw and Throws in some of our previous posts. Throw and Throws keyword are used in different scenarios while doing exception handling. In this post we see some basic difference between Throw and Throws. Difference between Throw

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Difference Between HashSet LinkedHashSet and TreeSet

HashSet, LinkedHashSet and TreeSet are all implementations of the Set interface.In this post lets see Difference Between HashSet LinkedHashSet and TreeSet. 1. Implementation All these 3 implement the Set interface. HashSet is backed by a hash table (actually a HashMap instance). LinkedHashSet

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TreeSet Example in Java

TreeSet is a NavigableSet implementation based on a TreeMap. Sorting in the TreeSet makes it different from the HashSet. In TreeSet the elements are sorted ascending using their nartural sorting order. You can change the sorting by providing a Comparator while constructing

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LinkedHashSet Example in Java

LinkedHashSet extends the HashSet and is the implementation of Hash Table and Linked List. LinkedHashSet maintains a doubly-linked list through all of its elements. This helps in maintaining the insertion-order of the elements. Since LinkedHashSet extends the HashSet, they have all the

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Merging Cells in Excel Using POI

Merging Cells in Excel using POI can be done using the [crayon-58aa09dbee79b632123268-i/] method. CellRangeAddress is the range of the rows and columns that need to be selected. In our case to be merged. The constructor of CellRangeAddress takes 4 params – [crayon-58aa09dbee7a4312750571-i/]

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User Defined Exceptions in Java

While working on an application, you may come across some scenarios where you feel like the Exceptions defined in the java platform are not enough to represent the error/issue you want to tell the end user. In that case you may choose

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Sorting TreeMap Using Comparator

TreeMap are sorted naturally using their Keys. If you have your objects as keys then Sorting TreeMap using Comparator is a good way to decide the map order. Lets see an example on how to use Comparator in a TreeMap 1. User

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WeakHashMap example in Java

WeakHashMap is a HashTable based implementation of the Map Interface. The keys of the WeakHashMap have weak reference and so an entry in a WeakHashMap will automatically be removed when its key is no longer in ordinary use. Each key object in

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LinkedHashMap example in Java

LinkedHashMap is part of the java.util package and it extends the HashMap, so it has all the properties of HashMap. LinkedHashMap maintains the order of insertion of the elements, hence when we iterate a LinkedHashMap we get the elements in the order

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