Therefore, it must throw a NumberFormatException. Let's try to break this code by inputting an invalid integer: String str = '25T' Īs you can see in the above code, we have tried to convert 25T to an integer. Let's consider an example of converting a string to an int using Integer.parseInt(): String str = '25' So, every time we convert a string to an int, we need to take care of this exception by placing the code inside the try-catch block. If the string does not contain a valid integer then it will throw a NumberFormatException. This method returns the string as a primitive type int. Use Integer.parseInt() to Convert a String to an Integer In Java, we can use Integer.valueOf() and Integer.parseInt() to convert a string to an integer. This leads us to the question – how can we convert a string to an integer? If we want to make a simple calculator using Swing, we need to figure out how to convert a string to an integer. If you have worked in Java Swing, it has components such as JTextField and JTextArea which we use to get our input from the GUI. String objects are represented as a string of characters.
