#1. Using Integer.parseInt()

Integer.parseInt() converts string value and returns an int primitive as result. For below example, first, we store 5 as a string value to id variable. Then convert it to integer and save to result variable.

Save the above content in ConvsertStringToInt1.java file and compile and run this program. Compile: Run:

#2. Using Integer.valueOf()

Integer.valueOf() also uses Integer.parseInt function in backend but in result, it provides and Integer object value.

Save the above content in ConvsertStringToInt2.java file and compile and run this program. Compile: Run:

#3. Exception in Conversion

If the given input is not parsable by the any of the above methods, NumberFormatException will be thrown. As in the below example, we are storing string”5abc” in id variable which contains alphabets. If we try to convert this number to int, NumberFormatException exception will occur.

Save the above content in ConvsertStringToInt3.java file and compile and run this program. Compile: Run: Reference: http://docs.oracle.com/javase/8/docs/api/java/lang/Integer.html