Oracle Java Developer Interview Questions, Process, and Tips

Generate all permutations of a given number without duplicates

• Use backtracking to generate all possible permutations

• Avoid duplicates by keeping track of used digits

• Recursively swap digits to generate permutations

To find the highest element in a BST, perform a right traversal until reaching the rightmost leaf node.

• Perform a right traversal starting from the root node until reaching the rightmost leaf node to find the highest element.

• Implement the insertion operation by comparing the value to be inserted with each node and traversing left or right accordingly.

• Ensure that the BST property is maintained during insertion by placing...read more

Heap Sort is a comparison-based sorting algorithm that uses a binary heap data structure.

• Heap Sort involves building a max heap from the input array, then repeatedly removing the maximum element and rebuilding the heap.

• The time complexity of Heap Sort is O(n log n) in the worst case scenario.

• Example: Given an array [4, 10, 3, 5, 1], after applying Heap Sort, the sorted array would be [1, 3, 4, 5, 10].

To delete the nth element from the end in a LinkedList, we can use two pointers approach.

• Use two pointers - one to traverse the list and another to keep track of the nth element from the end.

• Calculate the distance between the two pointers and delete the node at the second pointer.

To reverse a LinkedList, iterate through the list and change the direction of pointers.

• Iterate through the LinkedList and keep track of the previous, current, and next nodes.

• Update the pointers to reverse the direction of the nodes.

• Repeat until the end of the list is reached.

Explain the basics of Java in a simple and practical way, focusing on hands-on examples and real-world applications.

• Start by explaining the basic syntax and structure of Java code

• Use simple examples to demonstrate concepts like variables, loops, and functions

• Show how Java is used in real-world applications, such as building websites or mobile apps

Memory management is the process of controlling and coordinating computer memory, assigning portions called blocks to various running programs.

• Memory allocation - assigning memory blocks to programs as needed

• Memory deallocation - releasing memory blocks when no longer needed

• Memory fragmentation - the division of memory into small blocks leading to inefficient use

• Memory leaks - when a program fails to release memory aft...read more

Detect cycle in directed graph using depth-first search algorithm.

• Use depth-first search (DFS) algorithm to traverse the graph.

• Maintain a visited set to keep track of visited nodes.

• If a node is visited again during traversal, there is a cycle in the graph.