Difference Between .valueOf(), .toString() and parse methods in Java

In Java, “.valueOf()”, “.toString()”, and “parse methods” serve different purposes and are used with different data types. Here's an explanation of each:

1. .valueOf():

   - .valueOf() is a method that is often used to convert a primitive data type or a String to its corresponding wrapper class object.

   - For example, you can use “Integer.valueOf("123")” to convert the string "123" to an “Integer” object.

   - This method is available for most of the wrapper classes, such as “Integer”, “Double”, “Boolean”, etc.

   - It can also be used to obtain instances of enum types.

Example:

String str = "123";
Integer intValue = Integer.valueOf(str); // Converts the string to an Integer object

 

2. .toString():

   - .toString() is a method that is available for all objects in Java, and it is used to obtain a human-readable representation of an object as a String.

   - When you call “.toString()” on an object, it returns a String that typically includes information about the object's state.

   - You can also override the “.toString()” method in your custom classes to provide a custom string representation.

Example:

Integer intValue = 123;
String str = intValue.toString(); // Converts the Integer to a String

 

3. Parse methods:

   - Parse methods are used to convert a String representation of a value into the corresponding primitive data type or other data types.

   - The most common parse methods are “Integer.parseInt()”, “Double.parseDouble()”, “Boolean.parseBoolean()”, etc.

   - These methods take a String as input and return the parsed value in its respective primitive data type.

Example:

String str = "123";
int intValue = Integer.parseInt(str); // Converts the String to an int

It's important to note that when using parse methods, you should ensure that the input String is a valid representation of the target data type; otherwise, it may result in a “NumberFormatException” or similar exceptions. When using “.valueOf()”, you usually get an object of the wrapper class, which allows for more flexibility in handling null values.