Java object cast to boolean

How to convert String object to Boolean Object?

Autoboxing could also be used, but it has a performance cost.
I suggest to use it only when you would have to cast yourself, not when the cast is avoidable.

wouldn’t assigning Boolean.valueOf to boolaen2 be auto-unboxed anyway? I’m not seeing the difference to parseBoolean here.

The biggest problem is that Boolean will not exception out when it sees something it shouldn’t accept. It will return true for anything it sees as «true» and will return false for everything else. If you’re trying to enforce matching a string to an appropriate boolean value, you’ll have to add extra logic to catch illegal cases manually.

if String object is null then Boolean.valueOf(String) will return false .But Boolean can hold null value also .can you provide any help for this.

Because this is the top answer, could you update it to warn people not to use these dangerous methods? (I’m not aware of any good implementation in common libraries unfortunately.)

You have to be carefull when using Boolean.valueOf(string) or Boolean.parseBoolean(string). The reason for this is that the methods will always return false if the String is not equal to «true» (the case is ignored).

Because of that behaviour I would recommend to add some mechanism to ensure that the string which should be translated to a Boolean follows a specified format.

if (string.equalsIgnoreCase("true") || string.equalsIgnoreCase("false")) < Boolean.valueOf(string) // do something >else < // throw some exception >

This is the best example I’ve seen and what should have been implemented in the Boolean type to begin with. Throwing an exception for invalid Boolean value is important for many applications.

No thats not totally true. here is the underlying implementation of parseBoolean public static boolean parseBoolean(String s) < return ((s != null) && s.equalsIgnoreCase("true")); >

Heh. If you need to write such code, then you don’t need to call Boolean.valueOf. Instead you can simple restructure this if statement so it will do what you want 😉

Boolean b = Boolean.valueOf(string); 

The value of b is true if the string is not a null and equal to true (ignoring case).

Beside the excellent answer of KLE, we can also make something more flexible:

boolean b = string.equalsIgnoreCase("true") || string.equalsIgnoreCase("t") || string.equalsIgnoreCase("yes") || string.equalsIgnoreCase("y") || string.equalsIgnoreCase("sure") || string.equalsIgnoreCase("aye") || string.equalsIgnoreCase("oui") || string.equalsIgnoreCase("vrai"); 

(inspired by zlajo’s answer. :-))

boolean b = string.equalsIgnoreCase("true"); 

Well, as now in Jan, 2018, the best way for this is to use apache’s BooleanUtils.toBoolean .

This will convert any boolean like string to boolean, e.g. Y, yes, true, N, no, false, etc.

String[] values= new String[]; for(String booleanStr : values)

Str =N: boolean =false Str =Yes: boolean =true Str =YES: boolean =true Str =yes: boolean =true Str =no: boolean =false Str =No: boolean =false Str =NO: boolean =false Str =true: boolean =true Str =false: boolean =false Str =True: boolean =true Str =False: boolean =false Str =TRUE: boolean =true Str =FALSE: boolean =false Str =null: boolean =false 

Beware, BooleanUtils is still wrong (although less so than Boolean methods), as it will not throw exception if the value neither recognized as true , or false . So ture (a typo that someone does somewhere) is still blindly assumed to mean false . I can’t find anything in Guava either (like there’s no Booleans.stringConverter as of 23.0).

public static boolean stringToBool(String s) < s = s.toLowerCase(); SettrueSet = new HashSet(Arrays.asList("1", "true", "yes")); Set falseSet = new HashSet(Arrays.asList("0", "false", "no")); if (trueSet.contains(s)) return true; if (falseSet.contains(s)) return false; throw new IllegalArgumentException(s + " is not a boolean."); > 

My way to convert string to boolean.

For my case is mostly either 1 or true. I use hashes as dividers.

Why not use a regular expression ?

public static boolean toBoolean( String target )

We created soyuz-to library to simplify this problem (convert X to Y). It’s just a set of SO answers for similar questions. This might be strange to use the library for such a simple problem, but it really helps in a lot of similar cases.

import io.thedocs.soyuz.to; Boolean aBoolean = to.Boolean("true"); 

Please check it — it’s very simple and has a lot of other useful features

boolean status=false; if (variable.equalsIgnoreCase("true"))

This is supported only if the string is ‘true’ (not case-sensitive). Later you can play with the status variable.

Instead of status=Boolean.valueOf(variable) you could simply write status=true , because this line is only executed for values for which that method returns exactly that value.

If you’re aiming to just compare this string variable to a «false» or «true» string without hardcoding those two values, as was my case exactly, and you don’t want to use Boolean.valueOf() since it will return true for anything it sees as «true» and will return false for everything else, as Brandon pointed out, you can do the following.

if (someStringVariable.equals(Boolean.TRUE.toString()))

if (someStringVariable.equals(Boolean.FALSE.toString()))

To get the boolean value of a String, try this:

public boolean toBoolean(String s) < try < return Boolean.parseBoolean(s); // Successfully converted String to boolean >catch(Exception e) < return null; // There was some error, so return null. >> 

If there is an error, it will return null. Example:

toBoolean("true"); // Returns true toBoolean("tr.u;e"); // Returns null 

Have you tried this? 🙂 parseBoolean(String s) does not throw an exception, according to the Javadoc.

This will give you an idea of what to do.

This is what I get from the Java documentation:

Method Detail

parseBoolean

public static boolean parseBoolean(String s)

Parses the string argument as a boolean. The boolean returned represents the value true if the string argument is not null and is equal, ignoring case, to the string » true «.

Parameters:

s — the String containing the boolean representation to be parsed

Returns: the boolean represented by the string argument

Since: 1.5

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How to cast object to boolean in Java?

When working with the Java programming language, you may come across a scenario where you need to cast an Object to a boolean. This can be a bit tricky, as the Object class does not have a direct method for converting to a boolean. However, there are a few different approaches you can take to get the job done.

Method 1: Using instanceof

To cast an Object to a boolean in Java using instanceof , you can follow these steps:

1. Check if the Object is an instance of Boolean class using instanceof operator.
2. If it is an instance of Boolean, then cast it to Boolean and return its boolean value.
3. If it is not an instance of Boolean, then return false.

public static boolean castObjectToBoolean(Object obj)  if (obj instanceof Boolean)  return ((Boolean) obj).booleanValue(); > else  return false; > >

You can test this method with the following code:

Object obj1 = true; Object obj2 = "false"; Object obj3 = new Integer(1); System.out.println(castObjectToBoolean(obj1)); // Output: true System.out.println(castObjectToBoolean(obj2)); // Output: false System.out.println(castObjectToBoolean(obj3)); // Output: false

In this example, obj1 is an instance of Boolean with value true , so the method returns true . obj2 is a String with value «false» , so the method returns false . obj3 is an instance of Integer, so the method returns false .

Method 2: Using Boolean.parseBoolean()

To cast an Object to a boolean in Java using Boolean.parseBoolean() , follow these steps:

1. First, get the Object that you want to cast to a boolean.
2. Convert the Object to a String using the toString() method.
3. Use the Boolean.parseBoolean() method to convert the String to a boolean.

Here’s an example code snippet that demonstrates this:

Object obj = true; // Object to be cast to boolean String str = obj.toString(); // Convert Object to String boolean bool = Boolean.parseBoolean(str); // Convert String to boolean System.out.println(bool); // Output: true

In this example, we first initialize an Object obj with the boolean value true . We then convert obj to a String using the toString() method and store it in the variable str . Finally, we use the Boolean.parseBoolean() method to convert str to a boolean and store it in the variable bool . The output of the code is true .

Here’s another example that demonstrates casting an Object to a boolean when the Object is not a boolean:

Object obj = "true"; // Object to be cast to boolean String str = obj.toString(); // Convert Object to String boolean bool = Boolean.parseBoolean(str); // Convert String to boolean System.out.println(bool); // Output: true

In this example, we initialize an Object obj with the String value «true» . We then follow the same steps as before to convert obj to a boolean using Boolean.parseBoolean() . The output of the code is true .

That’s it! By following these steps, you can cast an Object to a boolean in Java using Boolean.parseBoolean() .

Method 3: Using the unboxing feature of Java

To cast an Object to boolean in Java using the unboxing feature, you can follow the steps below:

Step 1: Create an Object variable and assign it a value of either true or false.

Step 2: Cast the Object variable to a Boolean object using the casting operator.

Boolean boolObj = (Boolean) obj;

Step 3: Use the unboxing feature to convert the Boolean object to a boolean primitive.

boolean boolPrimitive = boolObj.booleanValue();

Alternatively, you can combine steps 2 and 3 into a single line by using the Boolean wrapper class’s valueOf() method, which returns a Boolean object.

boolean boolPrimitive = Boolean.valueOf(obj.toString());

public class ObjectToBooleanExample  public static void main(String[] args)  Object obj = false; Boolean boolObj = (Boolean) obj; boolean boolPrimitive = boolObj.booleanValue(); System.out.println("Boolean primitive value: " + boolPrimitive); // Alternatively, combine steps 2 and 3 into a single line boolean boolPrimitive2 = Boolean.valueOf(obj.toString()); System.out.println("Boolean primitive value (alternative method): " + boolPrimitive2); > >

Boolean primitive value: false Boolean primitive value (alternative method): false

Method 4: Using the Boolean.valueOf() method

To cast an Object to a boolean in Java using the Boolean.valueOf() method, follow these steps:

1. First, create an Object variable and assign it the value you want to cast. For example, let’s say we have an Object variable called myObject that contains a boolean value:

1. Next, use the Boolean.valueOf() method to cast the Object to a boolean. This method takes a String or a boolean as an argument and returns a Boolean object. To get the boolean value, call the booleanValue() method on the returned Boolean object. Here’s an example:

boolean myBoolean = Boolean.valueOf(myObject.toString()).booleanValue();

In this example, we first call the toString() method on the myObject variable to convert it to a String. Then, we pass this String to the Boolean.valueOf() method to create a Boolean object. Finally, we call the booleanValue() method on this object to get the boolean value.

Here’s another example that uses a boolean value as the argument for Boolean.valueOf() :

boolean myBoolean = Boolean.valueOf((Boolean) myObject).booleanValue();

In this example, we cast the myObject variable to a Boolean object using (Boolean) myObject , and then pass this Boolean object to the Boolean.valueOf() method.

That’s it! You now know how to cast an Object to a boolean in Java using the Boolean.valueOf() method.

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How to cast Object to boolean?

Casting an object to boolean is a common task in Java programming. This guide will show you how to cast an object to boolean in Java with code examples.

Method 1: Using Boolean.valueOf() method

The Boolean class provides a method called valueOf() that can be used to convert an object to boolean. Here’s an example:

Object obj = true; boolean bool = Boolean.valueOf(obj.toString()); 

In this example, we have an object `obj` that contains a boolean value. We convert the object to a string using the `toString()` method and then use `Boolean.valueOf()` to convert the string to a boolean value.

Method 2: Using instanceof operator

Another way to cast an object to boolean is by using the `instanceof` operator. Here’s an example:

Object obj = true; if (obj instanceof Boolean)

In this example, we check if the object `obj` is an instance of the Boolean class using the `instanceof` operator. If it is, we cast the object to boolean using `(Boolean) obj`.

Method 3: Using booleanValue() method

If you have an object of the Boolean class, you can use the `booleanValue()` method to convert it to a primitive boolean value. Here’s an example:

Boolean boolObj = true; boolean bool = boolObj.booleanValue(); 

In this example, we have an object `boolObj` of the Boolean class with a boolean value. We use the `booleanValue()` method to convert it to a primitive boolean value.

Conclusion

These are some of the ways to cast an object to boolean in Java. You can use any of these methods depending on your specific use case.

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