3 Ways To Convert String To Boolean Inwards Java? Examples

You tin terminate convert a String object to Boolean object or boolean primitive past times using the Boolean.valueOf() too Boolean.parseBoolean() method. The steps are similar rot converting to String to other information types e.g. String to Integer too String to Long. You tin terminate role valueOf() method to convert String to Boolean object too parseBoolean() method to convert given string to a boolean primitive value. Internally, valueOf() also uses parseBoolean() for parsing String but on overstep of that it also provides caching e.g. it tin terminate render Boolean.TRUE too Boolean.FALSE cached value for "true" too "false" string. 


In fact, the Boolean.TRUE is returned alone when String is equal to truthful ignoring instance e.g. "True", "true", "TRUE" volition evaluate into boolean true, therefore Boolean.TRUE volition hold out returned. For string similar "Yes", Boolean.FALSE volition hold out returned. We'll utter over the rules of String to boolean conversion inwards side past times side section.

1. Rules of String to Boolean Conversion inwards Java

The parsing logic is encapsulated inwards parseBoolean() method which is also leveraged or used past times valueOf(). According to this logic, the parseBoolean() method render truthful if given String is non null too equal to truthful ignoring instance too faux otherwise.

For example, "true", "True", too "TRUE" all volition render Boolean.TRUE value but "Yes" volition render Boolean.FALSE. Similarly, "false", "False", or "FALSE" volition also render Boolean.FALSE

Here are around examples:

Boolean.parseBoolean("True") returns true.
Boolean.parseBoolean("TRUE") returns true.
Boolean.parseBoolean("true") returns true.
Boolean.parseBoolean("yes") returns false.
Boolean.parseBoolean("y") returns false.
Boolean.parseBoolean("no") returns false.
Boolean.parseBoolean("false") returns false.
Boolean.parseBoolean("False") returns false.
Boolean.parseBoolean("FALSE") returns false.

If you lot desire to know to a greater extent than close how to convert 1 information type to others inwards Java,  The Complete Java Masterclass is a proficient resources to acquire it inwards depth.

2. Boolean.parseBoolean() Example

The parseBoolean() method is similar to parseInt() method too it returns a primitive boolean value afterward parsing given String. It returns a boolean value, true or false based upon the rules given above.

It compares String past times ignoring instance too alone render truthful if String matches truthful afterward ignoring cases.

Boolean.parseBoolean("True") returns true.
Boolean.parseBoolean("TRUE") returns true.
Boolean.parseBoolean("true") returns true.
Boolean.parseBoolean("yes") returns false.

You should role this method if you lot necessitate a primitive boolean value.

3. Boolean.valueOf() Example

This method should hold out used to convert a String object to a Boolean object inwards Java. It leverages the parsing logic of parseooleBan() method but it also uses the Flyweight pattern pattern to cache oft used value too returns them.

Since boolean tin terminate either hold out truthful or false, it but uses ii Boolean instances, Boolean.TRUE too Boolean.FALSE, for all String to Boolean conversion, which drastically reduces the publish of objects too causes less overhead for Garbage collector.

Here are around examples of converting String to Boolean using the valueOf() method:

Boolean.valueOf("True") returns Boolean.TRUE.
Boolean.valueOf("TRUE") returns Boolean.TRUE.
Boolean.valueOf("true") returns Boolean.TRUE.
Boolean.valueOf("yes") returns Boolean.FALSE.
Boolean.valueOf("y") returns Boolean.FALSE.
Boolean.valueOf("no") returns Boolean.FALSE.
Boolean.valueOf("false") returns Boolean.FALSE.
Boolean.valueOf("False") returns Boolean.FALSE.
Boolean.valueOf("FALSE") returns Boolean.FALSE.

You should role this method if you lot necessitate a Boolean object from String rather than boolean primitive value.  If you lot desire to know to a greater extent than close primitive information types inwards Java then Eclipse IDE too run. This programme accepts user input equally String too tries to convert it to a boolean. If successful, it prints that value into the console, otherwise, it throws an error.

package tool;  import java.util.Scanner;  /**  *   * Influenza A virus subtype H5N1 elementary Java Program to convert String to Boolean or boolean information type.  */ public class Hello {    public static void main(String[] args) {      System.out.println("Please acquire inwards a boolean String e.g. truthful or false");      Scanner sc = new Scanner(System.in);      String input = sc.next();      boolean b = Boolean.valueOf(input);      System.out.println("converted boolean value from String using valueOf: "         + b);      boolean value = Boolean.parseBoolean(input);      System.out         .println("converted boolean value from String using parseBoolean: "             + value);      sc.close();      // you lot tin terminate also role constructor but that is non encouraged past times Effective Java      Boolean bool = new Boolean(input);     System.out         .println("converted boolean value from String using constructor: "             + bool);    }  }  Output Please enter a boolean String e.g. true or false true converted boolean value from String using valueOf: true converted boolean value from String using parseBoolean: true converted boolean value from String using constructor: true

Here is the summary of all iii methods to convert String to Boolean inwards Java:

5. Important points

5.1 Even though you lot tin terminate also role the constructor of java.lang.Boolean class to convert String to a Boolean object, it's non encouraged by Effective Java of Joshua Bloch, which advice prefer static mill methods similar valueOf() to convey payoff of caching they offer.

5.2. The parsing rules i.e. how the string is genuinely converted into a boolean value is written inwards parseBoolean() method.

5.3 Both valueOf() too parseBoolean() method belongs to java.lang.Boolean class.

5.4. The valueOf() method render either the Boolean.TRUE or  Boolean.FALSE object, which is shared past times all boolean values converted.


That's all close how to convert String to Boolean or boolean inwards Java. As I said, you lot tin terminate role either Boolean.valueOf(), a static mill method or the parseBoolean() method for this conversion. The dominion of pollex is to prefer valueOf() if you lot necessitate Boolean object too parseBoolean() if you lot necessitate a boolean primitive value.

Further Learning

The Complete Java Masterclass
Java 10 Boolean Documentation

Core Java SE ix for the Impatient

Thanks for reading this article so far. If you lot similar this tutorial too so delight portion amongst your friends too colleagues. If you lot direct maintain whatever questions or feedback too so delight drib a note. 

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