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07 MATHEMATICAL LIBRARY
METHODS
Learning Objectives
7.1 “java.lang” Package 7.2 Mathematical Methods
To make programming in Java easy and simple, we need to create methods. Methods contain blocks of code written
to perform a specific task. Methods are generally used to solve complex problems; that doesn't mean they cannot
be used for simpler tasks. The advantage of using a method is that it can be reused. Methods are generally separate
from the main program, so if an error occurs in a method or if the code needs change, it is easy to make such changes.
There are two types of methods in Java: user-defined methods and library/system methods.
TYPES OF METHODS
USER DEFINED BUILT-IN/LIBRARY
1. User-defined methods: These methods are defined by the programmer as per requirements of the program.
2. Built-in/Library methods: These methods are already defined in the Java compiler and are stored as packages,
which are required to be imported before using them.
Let us learn about different types of built-in/library methods, which are string methods, mathematical methods,
graphic methods, etc.
7.1 "JAVA.LANG" PACKAGE
As you know, Java provides a wide variety of packages that contain a huge library of built-in classes. For example,
the “java.lang” package is a default package that contains classes and interfaces for the basic language functions.
In general, we have to import packages in our program to fetch the classes and interfaces that are defined in that
package. As “java.lang” is a default package, it is automatically imported by the Java compiler.
7.2 MATHEMATICAL METHODS
In Java, the Math class provides different types of mathematical methods. To use mathematical methods in
programs, we need to use the ‘Math’ class, which resides in the “java.lang” package.
140 Touchpad Computer Applications-IX

