Q) How to find out minor gc(garbage collection) vs major gc using gc logs
Ans:2014-11-18T16:39:37.728-0800: 88.808: [Full GC [PSYoungGen: 116544K->12164K(233024K)] [PSOldGen: 684832K->699071K(699072K)] 801376K->711236K(932096K) [PSPermGen: 2379K->2379K(21248K)], 3.4230220 secs] [Times: user=3.40 sys=0.02, real=3.42 secs]
In the above statement, gc means minor gc and Full gc means major/full gc.
https://dzone.com/articles/understanding-garbage-collection-log
http://karunsubramanian.com/websphere/troubleshooting-gc-step-by-step-instructions-to-analyze-verbose-gc-logs/
Q) How a marker interface works internally?
Q) What does ? super T and ? extends T mean in generics?
Ans http://www.oracle.com/technetwork/articles/java/juneau-generics-2255374.html
Q) Difference between port and porttype in a wsdl file
Ans: https://www.predic8.com/wsdl-reading.htm
Q) How to consume a webservice in Java/
Ans https://howtodoinjava.com/spring/spring-boot/spring-soap-client-webservicetemplate/
Q) How to render soap webservice over https?
Q) How do indexes work internally?
Ans http://www.dba-oracle.com/concepts/index_administration.htm
https://docs.oracle.com/cloud/latest/db112/CNCPT/indexiot.htm#CNCPT1170
Q) Why do indexes slow performance?
Q) Code review checklist
Ans https://www.java-success.com/30-java-code-review-checklist-items/
Q) Explain the significance of marker interface
Q) Garbage collection algorithms
Q) sort an arraylist with US, India, Canada at the top
Q) slow updates in prod..how to fix
Q) diff in Java memory model in java8
Q) difference between transient and static
Q) Does serialzation create same object or different object? How does JVM differentiates
Q) How does spring boot work internally
Q) what is ssl
Q) Hibernate child object is lazily loaded. What happens if you call get after a session close(LazyIntiialization exception)
Q) How to add an extra parameter from database in the entity class (Use transient)
Q) What logging is used in spring boot
Q) When does lazyinitialization exception occur
Q) Second level cache- When does it caches objects
Q) WHat are propagation levels
Q) What is metaspace
Q) How to mark an entity to be caches in second level cache (Use @Cacheacle)
Q) WHat are GC algorithms
Q) Production application -Slow Insertion-Steps to be taken
Q) How to create listener in angular application
Q) Benefits of Enum
Q) Program to find the number of repeated letters in a word
Q) Soft vs weak reference
Q) What is @embedded in hibernate
Q) Component vs contoller
Q) wsdl vs REST. why use soap?
Q) internal working of concurrenthashmap
Q) hashmap vs synchronized map
Q) Why REST is used so much?
Q) Two threads one genrate evn an other odd ?
Q) BlockingQueue
Q) An employee class with hascode returning 1 and equal returning "true". how many objects in the map if 3 are put?
Q) final list = new ArrayList(), Can i use list.set?
Q) Hww to customize serialization
Q) SOLID principles
Q) Aggregation vs composition
Q) Comparable vs comparator
Q) Clone method is in which class? How can we create a sutom marker interface?
Q) @ManytoMany Mapping in hibernate between two entities? How many tables?
Q) Bean scope in @RestController? How does it handle mutiple request?
Q) how to calcualte the frequency of a string in a list of 100 strings?
Ans: Use a map for keeping the count of a string
Q) How to create an immutable list - no cloning allowed
Q) How does @RestController handle multiple requests
Q) How does a servlet handle multiple requests?
Q) Two synchronized methods- two threads t1 and t2? Can they access at the same time?
Q) Fail fast and fail safe- How and why?
Q) Changes in Hashmap in java 8?
Q) Why are functional interfaces created?
Ans:2014-11-18T16:39:37.728-0800: 88.808: [Full GC [PSYoungGen: 116544K->12164K(233024K)] [PSOldGen: 684832K->699071K(699072K)] 801376K->711236K(932096K) [PSPermGen: 2379K->2379K(21248K)], 3.4230220 secs] [Times: user=3.40 sys=0.02, real=3.42 secs]
In the above statement, gc means minor gc and Full gc means major/full gc.
https://dzone.com/articles/understanding-garbage-collection-log
http://karunsubramanian.com/websphere/troubleshooting-gc-step-by-step-instructions-to-analyze-verbose-gc-logs/
Q) How a marker interface works internally?
Q) What does ? super T and ? extends T mean in generics?
Ans http://www.oracle.com/technetwork/articles/java/juneau-generics-2255374.html
Q) Difference between port and porttype in a wsdl file
Ans: https://www.predic8.com/wsdl-reading.htm
Q) How to consume a webservice in Java/
Ans https://howtodoinjava.com/spring/spring-boot/spring-soap-client-webservicetemplate/
Q) How to render soap webservice over https?
Q) How do indexes work internally?
Ans http://www.dba-oracle.com/concepts/index_administration.htm
https://docs.oracle.com/cloud/latest/db112/CNCPT/indexiot.htm#CNCPT1170
Q) Why do indexes slow performance?
Q) Code review checklist
Ans https://www.java-success.com/30-java-code-review-checklist-items/
Q) Explain the significance of marker interface
Q) Garbage collection algorithms
Q) sort an arraylist with US, India, Canada at the top
Q) slow updates in prod..how to fix
Q) diff in Java memory model in java8
Q) difference between transient and static
Q) Does serialzation create same object or different object? How does JVM differentiates
Q) How does spring boot work internally
Q) what is ssl
Q) Hibernate child object is lazily loaded. What happens if you call get after a session close(LazyIntiialization exception)
Q) How to add an extra parameter from database in the entity class (Use transient)
Q) What logging is used in spring boot
Q) When does lazyinitialization exception occur
Q) Second level cache- When does it caches objects
Q) WHat are propagation levels
Q) What is metaspace
Q) How to mark an entity to be caches in second level cache (Use @Cacheacle)
Q) WHat are GC algorithms
Q) Production application -Slow Insertion-Steps to be taken
Q) How to create listener in angular application
Q) Benefits of Enum
Q) Program to find the number of repeated letters in a word
Q) Soft vs weak reference
Q) What is @embedded in hibernate
Q) Component vs contoller
Q) wsdl vs REST. why use soap?
Q) internal working of concurrenthashmap
Q) hashmap vs synchronized map
Q) Why REST is used so much?
Q) Two threads one genrate evn an other odd ?
Q) BlockingQueue
Q) An employee class with hascode returning 1 and equal returning "true". how many objects in the map if 3 are put?
Q) final list = new ArrayList(), Can i use list.set?
Q) Hww to customize serialization
Q) SOLID principles
Q) Aggregation vs composition
Q) Comparable vs comparator
Q) Clone method is in which class? How can we create a sutom marker interface?
Q) @ManytoMany Mapping in hibernate between two entities? How many tables?
Q) Bean scope in @RestController? How does it handle mutiple request?
Q) how to calcualte the frequency of a string in a list of 100 strings?
Ans: Use a map
Q) How to create an immutable list - no cloning allowed
Q) How does @RestController handle multiple requests
Q) How does a servlet handle multiple requests?
Q) Two synchronized methods- two threads t1 and t2? Can they access at the same time?
Q) Fail fast and fail safe- How and why?
Q) Changes in Hashmap in java 8?
Q) Why are functional interfaces created?
Q) Microservices -static URLs /dynamic URLs
-----------------------------------------IRIS----------------------------------------------------------
Q) Design patterns - Prototype, Decorator
Q) sorting hashmap by value
Q) Custom hashmap- immutable
Q) SOLID principles - Examples
Q) Interface examples
Q) design patterns in Java libraries
Q) @Qualifier
Q) Reentrant lock -
Q) Predicate, Supplier , Consumer
Q) How to restrict to 3 objects only Q) Multiple default methods in one interface?
Q) ExecutorService-> new fixed thread pool vs cache pool
Q) Context Class Loader
Q) When the application is up and running, send an email to support team. Spring
Q) Design a cache - LRU and last read
Q) millions of customers- how to handle load- Design
Q) Check out of memory in production
Q) json to string?
Q) Hashmap key - hashcode and equals - Immutable - no setters, how to set
Q) How to validate a input json in REST
Q) Hibernate- cascading?
Q) How to handle transactions in hibernate
Q) How will you cache the data inside GET API mehtod
Q) Redis cache. How does it share data between microservics
Q) How do 2 APIs/microservices communicate with each other
Q) How to design an application with millions of users
-------------------------------------------------------------------------------------------------------
_________________________________________________________________________________
Ans Adapter
Q) In apache camel how do we integrate two different applications?
Q) There is an employee POJO. and a new field is required to be added without touching the existing code. What to do?
And Use inheritance
Q) How to reproduce a memory leak issue that occured in production environment to a local environment?
https://www.jahia.com/about-us/news-events/blog/tips-and-tricks-for-analyzing-java-virtual-machine-heap-memory-dumps
http://javaeesupportpatterns.blogspot.in/2011/11/hprof-memory-leak-analysis-tutorial.html
Q) Which collection to use in case of a lot of reads and few write operations?
Ans ArrayList
Q) Challenges faced in any projects?
_________________________________________________________________________________
Q) Which Java API should be used to fetch data from a legacy system?
Q) Use case- A weather service - How to reduce load on this service?
Ans Observer pattern
Q) Comparable vs comparator- which to use when?
Q) Things to keep in mind while designing a system?
Q) How to do performance management based on some input for an application?
Q) What happens if you call destroy from init in a servlet?
Q) Find third largest salaried employee in the employee table
________________________________________________________________________________
Q) how do you handle security in your application
Q) multithreading- fixed thread pool of 10 threads. 100 tasks are submitted. How many threads. how does submit and execute work internally.
Q) What does an angular application made of- where is template define. How to create an injectable service
Q) Where do you use functional interface in your application
Ans https://stackoverflow.com/questions/36881826/what-is-use-of-functional-interface-in-java-8/36882003?utm_medium=organic&utm_source=google_rich_qa&utm_campaign=google_rich_qa
Q) How do you use Apache camel in your application
Q) How to make a custom object as key to a hashmap in java 8
Ans https://dzone.com/articles/java-8-hashmaps-keys-and-the-comparable-interface
https://stackoverflow.com/questions/35164645/is-it-a-bug-that-java-8s-hashmap-misbehaves-if-the-keys-implement-comparable-in
https://www.javaworld.com/article/2073618/java-s-system-identityhashcode.html
Q) Why to use lambda expressions in java8?
Ans. https://www.nagarro.com/en/perspectives/post/26/Lambda-Expressions-in-Java-8-Why-and-How-to-Use-Them
Q) How does executor framework work internally. What does runnable.execute or callable.submit do?
Ans
Good links:
Functional interface uses: http://www.baeldung.com/java-8-lambda-expressions-tips
https://netjs.blogspot.in/2016/03/effectively-final-in-java-8.html
-->
_________________________________________________________________________________
Ericsson
Q) One java application wants to connect with a third party application. Which design pattern should be used?Ans Adapter
Q) In apache camel how do we integrate two different applications?
Q) There is an employee POJO. and a new field is required to be added without touching the existing code. What to do?
And Use inheritance
Q) How to reproduce a memory leak issue that occured in production environment to a local environment?
https://www.jahia.com/about-us/news-events/blog/tips-and-tricks-for-analyzing-java-virtual-machine-heap-memory-dumps
http://javaeesupportpatterns.blogspot.in/2011/11/hprof-memory-leak-analysis-tutorial.html
Q) Which collection to use in case of a lot of reads and few write operations?
Ans ArrayList
Q) Challenges faced in any projects?
_________________________________________________________________________________
Q) Which Java API should be used to fetch data from a legacy system?
Q) Use case- A weather service - How to reduce load on this service?
Ans Observer pattern
Q) Comparable vs comparator- which to use when?
Q) Things to keep in mind while designing a system?
Q) How to do performance management based on some input for an application?
Q) What happens if you call destroy from init in a servlet?
Q) Find third largest salaried employee in the employee table
________________________________________________________________________________
ING internal
Q) a function is not performing well in the application. What approach to find the problem. Environment is productionQ) how do you handle security in your application
Q) multithreading- fixed thread pool of 10 threads. 100 tasks are submitted. How many threads. how does submit and execute work internally.
Q) What does an angular application made of- where is template define. How to create an injectable service
Q) Where do you use functional interface in your application
Ans https://stackoverflow.com/questions/36881826/what-is-use-of-functional-interface-in-java-8/36882003?utm_medium=organic&utm_source=google_rich_qa&utm_campaign=google_rich_qa
Q) How do you use Apache camel in your application
Q) How to make a custom object as key to a hashmap in java 8
Ans https://dzone.com/articles/java-8-hashmaps-keys-and-the-comparable-interface
https://stackoverflow.com/questions/35164645/is-it-a-bug-that-java-8s-hashmap-misbehaves-if-the-keys-implement-comparable-in
https://www.javaworld.com/article/2073618/java-s-system-identityhashcode.html
Q) Why to use lambda expressions in java8?
Ans. https://www.nagarro.com/en/perspectives/post/26/Lambda-Expressions-in-Java-8-Why-and-How-to-Use-Them
Q) How does executor framework work internally. What does runnable.execute or callable.submit do?
Ans
Good links:
Functional interface uses: http://www.baeldung.com/java-8-lambda-expressions-tips
https://netjs.blogspot.in/2016/03/effectively-final-in-java-8.html
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