Introduction:
The java.lang
package is a fundamental part of the Java Standard Edition API, providing core classes and utilities that are automatically imported into every Java program. In this tutorial, we will explore some key classes in java.lang
and demonstrate their usage through practical examples.

1. Object Class:
The Object
class is the root of the Java class hierarchy. All classes inherit from this class, and it provides essential methods such as equals()
, hashCode()
, and toString()
. Let’s create a simple example:
2. String Class:
The String
class represents a sequence of characters and is widely used in Java programming. It provides various methods for manipulating strings. Here’s an example:
3. System Class:
The System
class provides access to the standard input, output, and error streams, as well as methods for interacting with the environment. Here’s an example of using System.out
for printing:
4. Math Class:
The Math
class contains methods for performing basic numeric operations, including trigonometry, exponential, logarithmic, and rounding functions. Example:
5. Wrapper Classes:
Java provides wrapper classes for primitive data types in java.lang
such as Integer
, Double
, Boolean
, etc. These classes allow primitive data types to be treated as objects. Example:
Conclusion:
The java.lang
package provides essential classes and utilities that form the foundation of Java programming. This tutorial covered some key classes like Object
, String
, System
, Math
, and wrapper classes, along with practical examples to illustrate their usage. As you delve deeper into Java development, a solid understanding of these core classes will prove invaluable.