Java Standard Library

Abstract

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• A collection of pre-written classes and interfaces provided by Oracle Corporation as part of the Java Development Kit (JDK)

java.util.*

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• Package in Java that provides a collection of Data Structure and Algorithm, not automatically imported

java.util.TreeSet

• Hash Map but with elements sorted, the time complexity is $O(logn)$ for insertion, deletion, search. $O(n)$ to list all elements in a sorted manner

java.util.Arrays

• For Arrays.sort(), the elements inside the Array must be a type of Object. int[] can’t, because int is a Primitive Datatype

java.util.ArrayDeque

• Doesn’t support null elements, but LinkedList can

java.lang.*

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• Core package in Java that is automatically imported into every Java program