Boolean Values In Java

Understanding Through Code

public class BooleanInJava {  	  	static boolean staticBool;  //Remember primitives are assigned defaults    	public static void main( String[] args ){  		  		boolean boolVal1 = true;  		boolean boolVal2 = false;    		System.out.println("boolVal1: " +boolVal1);  		System.out.println("boolVal2: " +boolVal2);  		System.out.println("staticBool: " +staticBool);    		boolean boolVal3 = !boolVal1;  //negation of boolVal1 is assigned to boolVal3    		System.out.println("boolVal3: " +boolVal3);    		int someInt = 1;  		boolean boolVal4 = (someInt != 1);  		System.out.println("boolVal4: " +boolVal4);    		String strBool = "false";  //this should be either true or false only    		boolean convertedBool = Boolean.parseBoolean(strBool);  		System.out.println("Parsing of boolean: " +convertedBool);    	}  }

Output

• boolVal1: true
• boolVal2: false
• staticBool: false
• boolVal3: false
• boolVal4: false
• Pasrsing of boolean: false

Notes:

• Unassigned boolean variable defaults to false.
• We can use negation (!) to switch boolean values from true to false or vice versa.
• Expressions result can be captured in boolean variable
  • E.g. someInt != 1;
• Boolean helper class lets you convert string to boolean type only if the string is either true or false.