A string is an object that represents a sequence of characters. Strings are commonly used to store and manipulate text. Java provides a built-in class called "String" that is used to handle strings.

Strings in Java are immutable, meaning that once a string object is created, it cannot be changed. When you perform operations on a string, such as concatenation or substring extraction, a new string object is created, and the original string remains unchanged.

Here are a few common operations you can perform with strings in Java:

• Concatenation: You can concatenate two or more strings using the "+" operator.

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

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• Substring: You can extract a substring from a string using the substring() method.

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• IndexOf: You can find the index of a specific character or substring within a string using the indexOf() method.

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• Equals: You can compare two strings to see if they are equal using the equals() method.

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• toLowerCase/toUpperCase: You can convert a string to all lowercase or all uppercase letters using the toLowerCase() and toUpperCase() methods, respectively.

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There are many other operations you can perform with strings in Java