Overview of Java Strings

Strings in Java are a sequence of characters and are widely used for handling text data. They are a fundamental part of Java programming, and understanding them is essential for any Java developer.

Key Concepts

• String Definition:
  • A String in Java is an object that represents a sequence of characters.
  • Strings are immutable, meaning once a String object is created, it cannot be changed.
• Creating Strings:
  • You can create a String in two ways:
• String Length:

You can find the length of a string using the length() method:

int length = str1.length(); // Returns 13

Using the new keyword:

String str2 = new String("Hello, World!");

Using double quotes:

String str1 = "Hello, World!";

Common String Methods

• Concatenation:
• Character Access:
• Substring:
• String Comparison:

Compare strings using equals() and compareTo() methods:

boolean isEqual = str1.equals(str2); // Checks for value equality
int comparison = str1.compareTo(str2); // Lexicographical comparison

Extract a portion of the string using substring(startIndex, endIndex):

String sub = str1.substring(0, 5); // Returns "Hello"

Access individual characters with the charAt(index) method:

char ch = str1.charAt(0); // Returns 'H'

Joining two or more strings using the + operator or concat() method:

String str3 = str1 + " How are you?"; // Using +
String str4 = str1.concat(" How are you?"); // Using concat()

Conclusion

Understanding strings is crucial for manipulating text in Java. They provide various methods for creation, modification, and comparison, making them versatile for many programming tasks. Remember that strings are immutable, and any operation that seems to modify a string will actually create a new string object.