Blog Archives

01: What is wrong with following Java code snippets? Auto-unboxing, switch, short circuit & exception

Auto-unboxing, switch, short circuit logical operators & exception handling are core Java basics that sometimes lead to obscure errors if not understood well & often tested in coding tests.

Q1.

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03: What is wrong with this code? Data types & equals( ) Vs, hashCode( ) contract

Q6. What is wring with this code?

A6. Infinite loop at due to sum != 1.0. Using floating point variables like float or double in loops to compare for equality can lead to infinite loops.

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04: What is wrong with this code? Java Collection & ConcurrentModificationException

Q9. What is wring with this code? A9. throws a Runtime exception called “java.util.ConcurrentModificationException” The output will be: Fix 1: Use iterator.remove() instead of collection.remove Output: Fix 2: Use java.util.…...



05: What is wrong with this code? Deep Vs Shallow comparison & multithreading

Q10 What is wring with this code? A10. date1 == date2 only compares the references and not the actual dates. Since both the references are different objects, … Read more...



06: What is Wrong with this code? Multithreading & wait/notify

An excellent written test question to assess your Java multi-threading knowledge. Please practice it by doing it yourself.

Q. Review the code shown below and then answer the following questions.

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07: What is wrong with this code? Multithreading & locks

Q. What is wrong with the following Java code? Explain what does the following code do? Explain if there is anything wrong with the following code? … Read more ›...



08: What is wrong with this code? Generics

Q. Can you review the following code and see if it has any issues? A. The “MyStack” class is not properly using “generics”. … Read more ›...



09: What is wrong with this code? HashMap & Race condition

Q. What is wrong with the following code snippet? A. It is NOT thread-safe as a “HashMap” is not thread-safe as per the Java API, … Read more ›...



10: What is wrong with this code? ConcurrentHashMap & Atomic operations

Q. What output is expected from the following code? What does it actually output? A. It is expected to output counts from 100,001 to 100,010, … Read more ›...



What is wrong with this Java code? Heap Vs Stack, Thread safety & Synchronized

This post covers must know Java Multithreading basics – Heap Vs Stack, Thread-safety & Synchronization. When you have a multithreaded Java application, you need to code in a thread-safe manner.

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