Free Java Interview Question And Answers Pdf [Quiz -6 ]

Java Interview Questions and Answers PDF

Java coding questions are an important part of technical interview preparation, especially for freshers and students applying for software development positions. Practicing small programming problems regularly can help candidates improve their understanding of Java syntax, logic building, loops, arrays, strings, and basic data handling.

In Java Interview Questions and Answers PDF – Quiz 6, we cover five programming problems that are useful for interview preparation. The questions focus on finding the largest value in an array, checking anagrams, generating the Fibonacci sequence, converting binary numbers into decimal values, and finding common elements between two arrays.

Each question includes a Java implementation along with an explanation of how the solution works. These examples can be used for practice before Java coding interviews and technical assessments.

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1. Find the

/Largest Element

Question: Write a Java function that accepts an integer array and returns the largest element present in that array.

One simple way to solve this problem is to assume that the first element is the largest value initially. The program then goes through the remaining elements one by one. Whenever it finds a value greater than the current maximum, that value becomes the new maximum.

The method also checks whether the supplied array is null or contains no elements. In either situation, an IllegalArgumentException is generated because there is no value available for comparison.

public class FindLargestElement {
    public static int findLargestElement(int[] array) {
        if (array == null || array.length == 0) {
            throw new IllegalArgumentException("Array must not be empty or null");
        }

        int maxElement = array[0];

        for (int element : array) {
            if (element > maxElement) {
                maxElement = element;
            }
        }

        return maxElement;
    }

    public static void main(String[] args) {
        int[] array = {12, 5, 27, 8, 18};

        System.out.println("Largest Element: " + findLargestElement(array));
    }
}

For the example array, the method compares all values and identifies 27 as the largest element.

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2. Check for Anagrams

Question: Create a Java program that checks whether two given strings are anagrams of each other.

Anagrams contain the same characters with the same frequencies, but the order of those characters can be different. For example, listen and silent contain identical characters and therefore qualify as anagrams.

The solution first removes whitespace and converts both strings to lowercase. Their characters are then converted into arrays and sorted. If the two sorted arrays contain the same characters, Arrays.equals() returns true.

import java.util.Arrays;

public class AnagramChecker {
    public static boolean areAnagrams(String str1, String str2) {
        char[] charArray1 = str1.replaceAll("[\s]", "").toLowerCase().toCharArray();
        char[] charArray2 = str2.replaceAll("[\s]", "").toLowerCase().toCharArray();

        Arrays.sort(charArray1);
        Arrays.sort(charArray2);

        return Arrays.equals(charArray1, charArray2);
    }

    public static void main(String[] args) {
        String word1 = "listen";
        String word2 = "silent";

        System.out.println("Are Anagrams: " + areAnagrams(word1, word2));
    }
}

This question is useful for practicing string manipulation, character arrays, sorting, and comparison methods in Java.

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3. Calculate Fibonacci Sequence

Question: Write a Java function that generates the Fibonacci sequence up to a specified limit.

The Fibonacci sequence begins with 0 and 1. Every number that follows is produced by adding the two values immediately before it. The program below uses two variables, a and b, to maintain the current pair of numbers.

During every iteration, the next Fibonacci value is calculated. The variables are then updated so the calculation can continue with the next pair of numbers.

public class FibonacciSequence {
    public static void generateFibonacci(int limit) {
        int a = 0, b = 1;

        System.out.print(a + " " + b + " ");

        for (int i = 2; i < limit; i++) {
            int next = a + b;

            System.out.print(next + " ");

            a = b;
            b = next;
        }
    }

    public static void main(String[] args) {
        int sequenceLimit = 10;

        generateFibonacci(sequenceLimit);
    }
}

With a limit of 10, the method generates the beginning portion of the Fibonacci sequence. This problem is useful for understanding loops, variable updates, and numerical sequences in Java.

4. Binary to Decimal Converter

Question: Implement a Java program or function that converts a binary number into its decimal equivalent.

Binary numbers use base 2, while decimal numbers use base 10. Java provides the Integer.parseInt() method with a radix argument, which makes this conversion straightforward.

In the following program, the value 2 is supplied as the radix. Java therefore interprets the input string as a binary number and returns the corresponding integer value.

public class BinaryToDecimalConverter {
    public static int binaryToDecimal(String binary) {
        return Integer.parseInt(binary, 2);
    }

    public static void main(String[] args) {
        String binaryNumber = "1101";

        System.out.println("Decimal Equivalent: " + binaryToDecimal(binaryNumber));
    }
}

For the example, the binary value 1101 is converted into its decimal equivalent. This is a useful interview problem for practicing number systems and Java’s built-in conversion methods.

5. Find Common Elements

Question: Write a Java function that accepts two arrays and returns the elements that appear in both arrays.

The provided solution compares each element of the first array against the values in the second array. When a matching value is found, it is stored inside an ArrayList. The inner loop stops after finding the match, preventing the same value from being added again for that comparison.

Once all comparisons are complete, the list is converted into an Integer array and returned by the method.

import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;

public class FindCommonElements {
    public static Integer[] findCommonElements(int[] array1, int[] array2) {
        List<Integer> commonElements = new ArrayList<>();

        for (int element1 : array1) {
            for (int element2 : array2) {
                if (element1 == element2) {
                    commonElements.add(element1);
                    break;
                }
            }
        }

        return commonElements.toArray(new Integer[0]);
    }

    public static void main(String[] args) {
        int[] array1 = {1, 2, 3, 4, 5};
        int[] array2 = {3, 5, 7, 9};

        System.out.println(
            "Common Elements: " +
            Arrays.toString(findCommonElements(array1, array2))
        );
    }
}

For the example arrays, the values shared by both arrays are 3 and 5. This question provides practice with nested loops, arrays, lists, and comparisons.

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Frequently Asked Questions

Are these Java interview questions useful for freshers?

Yes. These problems focus on fundamental programming concepts that are useful for candidates beginning their Java interview preparation. They provide practice with arrays, strings, loops, numerical operations, and basic collection handling.

What topics are covered in Java Quiz 6?

This quiz contains five topics: finding the largest array element, checking whether strings are anagrams, generating Fibonacci numbers, converting binary to decimal, and identifying common elements in two arrays.

How should I practice these Java coding questions?

First understand the problem statement and try to write the logic independently. After that, compare your solution with the example implementation. Repeating the process with different input values can help strengthen programming practice.

What is an anagram?

An anagram is a word or string formed using the same characters and frequencies as another string, but the characters may occur in a different order. The example listen and silent demonstrates this concept.

What is the Fibonacci sequence?

The Fibonacci sequence starts with 0 and 1. Each new value is calculated by adding the two previous values. The sequence is commonly used as a basic programming problem for practicing loops and mathematical logic.

How does Java convert binary into decimal?

The example uses Integer.parseInt(binary, 2). The second argument specifies base 2, allowing Java to interpret the supplied string as a binary number and return its decimal value.

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