What is try-with-resources in java?

Question

Implement a code that counts the occurrences of each word in an input file and write the word along with corresponding count in an output file sorted by the words alphabetically.

Sample Input

Gaurav is  a Good Boy
Sita is a Good Girl
Tommy is  a Good Dog
Ram is a Good person

Sample Output

D:\>Java FileWordCount inputFile.txt outputFile.txt
    Boy : 1
    Dog : 1
    Gaurav : 1
    Girl : 1
    Good : 4
    Ram : 1
    Sita : 1
    Tommy : 1
    a : 4
    is : 4
    person : 1

Answer 1

try-with-resources is an interesting concept in java. The purpose of this is to auto dispose/close the resource as soon as it serves its purpose.

For instance in Java 6 and below, a buffer reader is initialized and closed manually in try's finally block.

BufferedReader br = new BufferedReader(new FileReader(path));
    try {
        return br.readLine();
    } finally {
        if (br != null) br.close();
}

Now, with try-with-resources, (started supported BufferedReader from Java 7) it is automatically closed as soon the try statement block executes completely. It closes automatically, irrespective of success or error of try block.

try (BufferedReader br = new BufferedReader(new FileReader(path))) {
     return br.readLine();
}

Note: java.lang.AutoCloseable must be implemented for any class to support try-with-resources.

Hope this helps.