In This Article, You Will Learn about Java String.
Java String – Before moving ahead, let’s know a bit about Method Overloading in Java.
Table of Contents
String
A String is used to store the sequence of characters in double quotes.
Note: String is a data type too in Java.
Example: Create a variable of type String and assign a value.
String name = "Alex"
String Methods
String Length
A String in Java is an object which contains a method that can perform operations on strings. One of the methods of the string is finding out the length of the string by length() method.
String name = "Mississippi River";
System.out.println("The length of the name string is: " + name.length());
charAt() Method
The charAt() method returns the character at the specified index in a string. The index of the first character is 0, the second character is 1, and so on.
Syntax
public char charAt(int index)
Example: Find the character at index number 8.
String name = "Mississippi River";
char result = name.charAt(8);
System.out.println(result)
endsWith() Method
The endsWith() method checks whether a string ends with the specified character(s).
Syntax
public boolean endsWith(String chars)
Example: Check whether the given string ends with a specified character or not.
String name = "Mississippi River";
System.out.println(name.endsWith("er")); // true
System.out.println(name.endsWith("e")); // false
System.out.println(name.endsWith("iver")); // true
startsWith() Method
The startsWith() method checks whether a string starts with the specified character(s).
Syntax
public boolean startsWith(String chars)
Example: Check whether the given string starts with a specified character or not.
String name = "Mississippi River";
System.out.println(name.startsWith("Mi")); // true
System.out.println(name.startsWith("ssi")); // false
System.out.println(name.startsWith("iver")); // false
toLowerCase() Method
The toLowerCase() method converts a string to lower case letters.
Syntax
public String toLowerCase()
Example: Use toLowerCase() method to convert a string to lower case letters.
String name = "Mississippi River";
System.out.println(name.toLowerCase());
toUpperCase() Method
The toUpperCase() method converts a string to upper case letters.
Syntax
public String toUpperCase()
Example: Use toUpperCase() method to convert a string to upper case letters.
String name = "Mississippi River";
System.out.println(name.toUpperCase());
Later in lesson you will learn more about Java String Methods.
Java String Concatenation
String Concatenation
String Concatenation – String Concatenation is the process of concatenating two or more strings by using the + operator.
Example: Use + operator to perform concatenation between strings.
String name1 = "Mississippi";
String name2 = "River";
System.out.println("The concatenation of the strings are: " + name1 + " " + name2);
Java Numbers and Strings
Adding Numbers and Strings
Note: Java uses the + operator for both addition and concatenation.
The addition is used for Numbers.
Concatenation is used for Strings.
Example: Use + operator to add two numbers.
int x = 10;
int y = 20;
int z = x + y;
System.out.println("The addition of the x + y + z are: " z);
Example: Use + operator to perform operation on the string.
String num1 = "01";
String num2 = "02";
System.out.println("The concatenation of the strings are: " + num1 + " " + num2);
Example: Use + operator to perform operation on both string and number.
String num1 = "01";
int y = 20;
String z = x + y;
System.out.println("The output is: " + z);
Output: Incompatible types: String cannot be converted to int.
Java Special Characters
Strings – Special Characters
Since, the string is written inside the double quote; therefore Java returns an error.
String sentenceLine = “I love to do coding “and taking tutorial” from codingstreets.”;
To avoid the error, Java uses the backslash escape character.
The backslash (\) escape character turns special characters into string characters:
Escape character | Result | Description |
\’ | ‘ | Single quote |
\” | “ | Double quote |
\\ | \ | Backslash |
\n | New Line | |
\r | Carriage Return | |
\t | Tab | |
\b | Backspace |
The sequence \’ inserts a single quote in a string:
Example:
public class Main {
public static void main(String[] args) {
String line1 = "I\'m okay.";
System.out.println(line1);
}
}
The sequence \” inserts a double quote in a string:
Example:
public class Main {
public static void main(String[] args) {
String line2 = "I love to do coding \"and taking tutorial\" from codingstreets.";
System.out.println(line2);
}
}
The sequence \\ inserts a single backslash in a string:
Example:
public class Main {
public static void main(String[] args) {
String line3 = "The character \\ is called backslash.";
System.out.println(line3);
}
}
It \n inserts a new line.
Example:
public class Main {
public static void main(String[] args) {
String line1 = "I love to \n learn coding.";
System.out.println(line1);
}
}
Example:
public class Main {
public static void main(String[] args) {
String line1 = "I love to \r learn coding.";
System.out.println(line1);
}
}
It \t inserts tab size.
Example:
public class Main {
public static void main(String[] args) {
String line1 = "I love to \t learn coding.";
System.out.println(line1);
}
}
It \b inserts backspace.
Example:
public class Main {
public static void main(String[] args) {
String line1 = "I love to lea\brn coding.";
System.out.println(line1);
}
}
