Java String (Medium)

Java Strings

• The String class is used to create and manipulate strings in Java.

String Definition

• A sequence of characters written inside double-quotes is referred to as a string literal.

String Characteristics

• Strings in Java are immutable, meaning they cannot be changed once created.
• Strings are stored in the string pool in Java.

String Operations

• When a string operation is performed in Java, a new string is created, and the original string remains unchanged.

Creating Strings

• There are two methods to create strings in Java: using the String keyword and using the new keyword.

String Methods

• The length() method is used to find the length of a string in Java.
• The equals() method is used to compare two strings and return 0 if they are equal.
• The concat() method is used to concatenate two strings in Java.
• The toUpperCase() method is used to convert a string to upper case in Java.
• The charAt() method is used to find the character at a specific index in a string.
• The String.format() method is used to create a formatted string in Java.
• The substring() method is used to get a substring from a given string starting from a specified index till the end of the string.
• The contains() method is used to check if a string contains a particular substring.
• The replaceAll() method is used to replace all occurrences of a string in another string.
• The replaceFirst() method is used to replace only the first occurrence of a string in another string.
• The indexOf() method is used to find the index of a character or a string from a given string.
• The trim() method is used to remove extra spaces from the beginning and end of a string.
• The lastIndexOf() method is used to find the last occurrence of a character or a string in a given string.
• The isEmpty() method is used to check whether a string is empty or not.
• The split() method is used to split a string based on a delimiter/regular expression.

String Methods Examples

• The output of the code String str = "Java Programming"; System.out.println(str.lastIndexOf("a")); is 15.
• The output of the code String str = "Java Programming"; System.out.println(str.lastIndexOf('a', 5)); is 4.

Importance of String Methods

• The purpose of string methods in Java is to perform various operations on strings, such as manipulation, comparison, and searching.
• It is important to learn and understand string methods in Java because they are widely used in programming and can help you achieve efficient and effective coding.
• Practice and familiarity with string methods can help you achieve better programming skills and solve complex problems.