Top 50 core Java interview questions covering core Java concepts with diagrams, code, examples, and scenarios. If you don’t get these Java interview questions right, you will not be getting an offer.
== Vs equals(…)
Q1. What is the difference between “==” and “equals(…)” in comparing Java String objects?
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Hierarchical data with parent & child relationships are very common, and Java collection does not have a Tree data structure, hence it is a popular interview question. Further questions include tree data structure processing using recursiion & iteration. A Tree data structure can be represented as shown below.
Step 1: A simple Node.java class that encapsulates its value,
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Q1 How do you remove the Control-M characters from a file?
A1 Control-M is a carriage return on keyboard. The ^M is the keyboard equivalent to \r. In a file originated from DOS/Windows the \r\n is used for an end of line carriage return, whereas in Unix it is \n for a new line.
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Multithreading is one of the important features of Java, and multithreading interview Q&As can reveal a lot about your depth of core Java knowledge. Most importantly, it is not easy to grasp multithreading concepts without lots of hands-on experience. Let’s start with the beginner basics & then get into Java concurrency management interview Q&As for the experienced.
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One of the very frequently asked open-ended interview questions for anyone experienced is: Can you describe the high-level architecture of a recent application you had worked on? You can be asked:
1) to draw an architectural diagram on a white board and
2) to provide a brief description of the architecture,
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Spring framework interview questions are very common for the Java programmer jobs. This covers Spring framework beginner interview questions on the Spring core and more advanced Spring framework interview questions at Java microservices interview questions.
Q1. What do you understand by the terms Dependency Inversion Principle (DIP),
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This extends Kubernetes (i.e. Minikube) – deploy a node js service.
Docker containers & Kubernetes for deploying Spring Boot microservices. As mentioned earlier in Kubernetes, Docker & Microservices interview Questions & Answers.
Docker gives you application isolation, and solves the dependency hell issues.
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Mistake #1: Using floating point data types like float or double for monetary calculations. This can lead to rounding issues.
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package com.monetary; import java.math.BigDecimal; public class MonetaryCalc { public static void main(String[] args) { System.out.println(1.05 - 0.42); //1: $0.6300000000000001 //2: $0.63 System.out.println(new BigDecimal("1.05") .subtract(new BigDecimal("0.42"))); //3: $0.630000000000000059952043329758453182876110076904296875 System.out.println(new BigDecimal(1.05) .subtract(new BigDecimal(0.42))); //4: $0.63 System.out.println(BigDecimal.valueOf(1.05) .subtract(BigDecimal.valueOf(0.42))); System.out.println(105 - 42); //5: 63 cents } } |
In the above code, 2, 4, and 5 are correct and 1 and 3 are incorrect usage leading to rounding issues.
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Requirements gathering
Analysis
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A distributed system consists of multiple software components that are on multiple computers (aka nodes), but run as a single system. These components can be stateful, stateless, or serverless, and these components can be created in different languages running on hybrid environments, using open-source technologies, open standards, and interoperability.
Q01.
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Most interviews start with these 15 open-ended questions. These are ice breaker interview questions with no right or wrong answers to ease nervousness, but the quality of the answers can make a good first impression. Your answer can reveal a lot about your experience &
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Java Engineers, Big Data Engineers & Java/Big Data Architects must have a good handle on these 16+ Tech Key areas. You can talk the talk in Java or Big Data job interviews & also walk the walk by gaining a reputation as a go to person.
These 17 beginner Java interview questions & answers are not only for the entry level job interviews, but also get a good grasp of the beginner level Java concepts.
Q1. Why use Java?
A1. Java is a very popular language as per the TIOBE index.
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I have a good news, I got job offer. I like to share with you from my bottom of my heart feeling thankful to you.