3 ways : Convert String to Boolean in Java with Examples

In this tutorial, I will be sharing 3 ways to convert String to Boolean object or String to boolean (primitive data type).You can convert String to boolean primitive using Boolean class parseBoolean(String str) method. To convert String to Boolean object there are two ways, one using valueOf(boolean) method and other using Boolean class constructor. I will be sharing why you should prefer valueOf(String) method over Boolean class constructor. 

Read Also :  Convert double to int in java


1. Convert String to boolean primitive using Boolean.parseBoolean() method
2. Convert String to Boolean object using Boolean.valueOf() method [Preferred]
3. Convert String to Boolean object using constructor of Boolean class [Not Recommended]

1. Convert String to boolean primitive : Using Boolean.parseBoolean(String str)

You can convert String to boolean primitive by using Boolean.parseBoolean(String str) method.
According to Oracle docs,
The boolean returned by the method parseBoolean(String str) represents the value true if the string argument str is not null and is equal, ignoring case, to the string "true".
For example,

Boolean.parseBoolean("tRue") returns true
Boolean.parseBoolean("True") returns true
Boolean.parseBoolean("tRUE") returns true
Boolean.parseBoolean("yes") returns false
Boolean.parseBoolean("JavaHungry") returns false



public class StringtoBooleanPrimitive {
    public static void main(String args[]) {
        // Creating String Objects
        String str1 = "TruE";
        String str2 = "hello"; 
 
        /* Converting String Objects to boolean 
        using Boolean class parseBoolean() method*/
        boolean bool1 = Boolean.parseBoolean(str1);
        boolean bool2 = Boolean.parseBoolean(str2); 
 
        // Printing the Boolean values
        System.out.println("Convert String to boolean primitive : " + bool1);
        System.out.println("Convert String to boolean primitive : " + bool2);
    }
}

Output :
Convert String to boolean primitive : true
Convert String to boolean primitive : false


2. Convert String to Boolean Object : Using Boolean.valueOf(String str)

valueOf() returns Boolean instance representing the specified string.
According to Oracle docs,
The Boolean object returned by the method valueOf(String str) represents the value true if the string argument str is not null and is equal, ignoring case, to the string "true". 
For example,

Boolean.valueOf("tRue") returns true
Boolean.valueOf("True") returns true
Boolean.valueOf("tRUE") returns true
Boolean.valueOf("yes") returns false
Boolean.valueOf("JavaHungry") returns false
 
This method should be preferred over constructor Boolean(boolean) to convert String to Boolean object.Because this method yields significantly better space and time complexity.

public class StringtoBooleanObject {
    public static void main(String args[]) {
        // Creating String Objects
        String str1 = "TruE";
        String str2 = "hello"; 
        String str3 = "false"; 

        /* Converting String Objects to Boolean Object 
        using Boolean class valueOf() method */
        Boolean bool1 = Boolean.valueOf(str1);
        Boolean bool2 = Boolean.valueOf(str2); 
        Boolean bool3 = Boolean.valueOf(str3); 
 
        // Printing the Boolean values
        System.out.println("Convert String to Boolean Object : " + bool1);
        System.out.println("Convert String to Boolean Object : " + bool2);
        System.out.println("Convert String to Boolean Object : " + bool3);        
    }
}

Output :
Convert String to Boolean Object : true
Convert String to Boolean Object : false
Convert String to Boolean Object : false

3. Convert String to Boolean Object :  Using Boolean Class Constructor

This method is not recommended to convert String to Boolean object. Joshua Bloch, author of the book Effective Java, himself recommended using static factory methods like valueOf(String str) as they offer caching which significantly improves space and time complexity.

public class StringtoBooleanObject {
    public static void main(String args[]) {
        // Creating String Objects
        String str1 = "TruE";
        String str2 = "false"; 

        /* Converting String Objects to Boolean Object
        using Boolean Constructor */  
        Boolean bool1 = new Boolean(str1);
        Boolean bool2 = new Boolean(str2); 

        // Printing the Boolean values
        System.out.println("Convert String to Boolean Object : " + bool1);
        System.out.println("Convert String to Boolean Object : " + bool2);
    }
}

Output :
Convert String to Boolean Object : true
Convert String to Boolean Object : false

Note : Both valueOf(String str) and parseBoolean(String str) methods are present in the Boolean class

In the above article I have demonstrated 3 ways to convert String to Boolean primitive or Boolean Object in Java with Examples.If you have any questions regarding this topic then please mention in the comments.

About The Author

Subham Mittal has worked in Oracle for 3 years .
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