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02: HTTP basics on headers, MIME types, & cookies for Java developers

Q1. What happens when you open up a browser and type a URL to request a Web page or RESTFul web service data? A1. HTTP is a stateless protocol on top …

03: Identifying and fixing NonUniqueObjectException in Hibernate

NonUniqueObjectException is thrown when there is an object already associated with the session with the same id (primary key) (i.e. a duplicate). It is important to understand the concept of a …

04: Identifying and fixing LazyInitializationException in Hibernate

LazyInitializationException is thrown when an object becomes detached, and if you try to access associated (i.e. proxied) object(s) of a detached object.

Q. What is a detached object in Hibernate?

When …

05: Debugging Hibernate & handling 4 common issues

#1. Enable Logging in your log4j.xml,, or myapp-logback.xml

In the file, you can enable Hibernate SQL logging as shown below

06: Debugging NoSuchBeanDefinitionException in Spring

#1. Adding the @Named annotation to the interface instead of the implementation Adding the @Named, @Component, @Repository, etc annotation on the interface as opposed to the implementation class. The code below …

07: Debugging Spring Transaction Management

Never just trust that adding @Transactional annotation is going to create a transactional boundary for your service layer. EventRestController –> EventMergeProcesorImpl –> EventControlDAOImpl The @Transactional annotations added to “public” methods of …

5 Ways to debug thread-safety issues in Java

Interviewers often judge your experience with debugging skills. For example, debugging jar hell issues, debugging SSL issues, debugging hibernate issues, debugging transaction management issues, etc. All these are covered in detail …

7 Java debugging interview questions & answers

Q1. How would you go about debugging thread-safety or concurrency issues? A1. #1: Manually reviewing the code for any obvious thread-safety issues. Good knowledge of multi-threading is required. #2: List all …

Chrome Postman to test and debug RESTful Web Services

Step 1 You need to get the Postman extension for the Google chrome browser.

Step 2 Search and add POSTMAN.

Step 3 Once installed, open it from the Apps link.



Debugging “NoSuchMethodError” in Java

The JAR hell issues also lead to exceptions like NoSuchMethodError or IllegalArgumentException. I have already discussed debugging JAR Hell issues. #1 Check the war file for any duplicate versions of the …

Debugging connection refused issues in Java with 9 tips

Possible reasons for “refused connections” 1) Client & Server are not connected by the LAN. For example, they can be in the different zones. 2) The Server might not be running. …

Debugging JAR hell issues in Java

The following 3 questions are frequently asked by Java developers as an industrial strength Java project will have 100+ jar files. How often have you come across a Java application that requires different …

Debugging Java version issues

1. Error: Unsupported major.minor version 51.0 error?

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