Java - Long parseLong() method

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Description

The Java Long parseLong(String s) method parses the string argument s as a signed decimal long.

Declaration

Following is the declaration for java.lang.Long.parseLong() method

public static long parseLong(String s) throws NumberFormatException

Parameters

s − This is a String containing the long representation to be parsed.

Return Value

This method returns the long value represented by the argument in decimal.

Exception

NumberFormatException − if the string does not contain a parsable long.

Getting a long value from a String Containing Positive Decimal Number Example

The following example shows the usage of Long parseLong() method to parse a Long object from a string containing decimal number. We've created a String variable and assign it a string containing decimal number. Then using parseLong method, we're obtaining the Long object and printing it.

package com.tutorialspoint;

public class LongDemo {
   public static void main(String[] args) {   
      String str = "50";
      /* returns an Long object holding the long value represented
         by string str */
      System.out.println("Number = " + Long.parseLong(str)); 
   }
}

Output

Let us compile and run the above program, this will produce the following result −

Number = 50

Getting a long value from a String Containing Negative Decimal Number Example

The following example shows the usage of Long parseLong() method to get a Long object from a string containing a negative decimal number. We've created a String variable and assign it a string containing a negative decimal number. Then using parseLong method, we're obtaining the Long object and printing it.

package com.tutorialspoint;

public class LongDemo {
   public static void main(String[] args) {    
      String str = "-50";
      /* returns an Long object holding the long value represented
         by string str */
      System.out.println("Number = " + Long.parseLong(str)); 
   }
}

Output

Let us compile and run the above program, this will produce the following result −

Number = -50

Facing Exception while Getting a long value from a String Containing Invalid Number Example

The following example shows the usage of Long parseLong() method to get a Long object from a string containing a octal number. We've created a String variable and assign it a string containing an octal number. Then using parseLong method, we're trying to obtain an Long object and exception will be raised.

package com.tutorialspoint;

public class LongDemo {
   public static void main(String[] args) {    
      String str = "0x3";
      /* returns an Long object holding the long value represented
         by string str */
      System.out.println("Number = " + Long.parseLong(str)); 
   }
}

Output

Let us compile and run the above program, this will produce the following result −

Exception in thread "main" java.lang.NumberFormatException: For input string: "0x3"
	at java.lang.NumberFormatException.forInputString(Unknown Source)
	at java.lang.Long.parseLong(Unknown Source)
	at java.lang.Long.parseLong(Unknown Source)
	at com.tutorialspoint.LongDemo.main(LongDemo.java:10)