What is difference between error & exception in java (class hierarchy/ example)
We will discuss the difference between error & exception in java. We will demonstrate exception class hierarchy in java. We […]
Simulate or generate Out of memory error in java (with example)
What is OutOfMemoryError ? The OutOfMemoryError is thrown by JVM, when JVM does not have enough available memory, to allocate. OutOfMemoryError falls
Create or simulate deadlock in multi threading (concurrency/ java/ example)
Create & simulation deadlock situation using multiple threads (concurrency). Cyclic dependency of resource results in deadlock (example/java)
Difference between throw, throws & Throwable in java (with example).
1. What is throw in java? throw is a keyword in java. When an exceptional or unintended situation occurs in
Three Fruit basket puzzle (Baskets of apples, oranges & mixed fruits)
Three Fruit basket puzzle: There are 3 baskets or boxes containing apples, oranges and mixed fruits (apples and oranges). Apple
100 prisoners & a light bulb puzzle
100 prisoners & a light bulb puzzle: There are 100 prisoners in the prison cells. Prisoners cannot communicate with each
Find a way to Heaven or Hell (doorkeeper puzzle)
Way to Heaven or Hell puzzle You are standing in front of two doors, one door leads to heaven and
Difference b/w final, finally & finalize in java (with examples)
Let us discuss final, finally and finalize in java with code examples. What is final ? final is a keyword
Program to create immutable (thread safe) class in java (example)
1. What is immutable class? The class whose state does not change after its construction is called immutable class. There
Difference between StringBuilder & StringBuffer in java (example)
StringBuilder and StringBuffer are mutable classes StringBuilder & StringBuffer are mostly used, when we expects the modifications in string. e.g. Join two
Join or concatenate or combine multiple strings in java (example)
1. Different methods to join or concatenate strings in java Join String using + operator Combine String using String concat method Contact String
Primitive streams example in java8 (IntStream, LongStream, DoubleStream)
Java stream library have streams specifically for primitive types like int, long, double etc. With primitive streams, values are directly
groupBy, mapping & statistics features in Java8 lambda stream (examples)
Java 8 Stream: groupBy, mapping and statistics, lambda stream example. Discussed IntSummaryStatistics (min,max,avg) of List of Person objects.
Dutch national flag problem or Sort array containing 0s, 1s & 2s in java
Given an array containing unsorted integers 0,1 & 2. Sort the given input array using non recursive method. Dutch national flag
Sort an integer array using mergesort algorithm in java (with example)
What is merge sort algorithm? Merge sort(or MergeSort) is efficient, comparison based algorithm. The properties of merge sort algorithm are
Sort integer array in java using quicksort algorithm (example)
Given unsorted array in java, Sort integer array – Quick sort (partition-exchange) algorithm. Quick sort is divide & conquer algo. complexity : O(n log n).
Override JsonInclude properties – ObjectMapper ContextResolver (Jersey)
Given the model annotated with @JsonInclude annotation. Sometime the model objects are in third party jars or libraries, so we
RESTFul web service serialize non null & date field (jersey /objectmapper /contextresolver)
Given a user defined object or POJO having null fields (i.e. some fields are null). When we are serializing object the null
Do not serialize empty values – Jackson objectmapper (@JsonInclude)
Given an list of user defined objects or POJO and object may contains the empty values (e.g. null values or
Do not serialize null values – jackson objectMapper (@JsonInclude)
Given a list of user defined objects or POJO and object may contains the null values. When we are converting
Do not serialize empty values of object – Jackson ObjectMapper (example)
Given a list of user defined objects or POJO and object may contains the empty values (e.g. null values or
Serialize non null values of list of objects – Jackson ObjectMapper (example)
Given the list of user defined objects or POJO and object may contains null values. When we are converting list
Sort an integer array using insertion sort algorithm in java (with example)
What is insertion sort algorithm? Insertion sort is a sorting technique. The elements are inserted at an appropriate place in an
Convert Enum to / from Integer & String value in java (example)
Given an enum in java. Convert enum to integer & vice Versa. Convert enum to string value & vice Versa.
Create temporary file in a temp or input directory – java (example)
Create a temporary file in java. We can create temporary file by specifying prefix, suffix (or directory) We will demonstrate
Sort an integer array using selection sort algorithm in java (with example)
What is selection sort algorithm? Selection sort is sorting technique used to sort the elements in list data structure like array.
Sort integer array using bubble sort algorithm in java (example)
Given an unsorted array in java. Sort the given input array using bubble sort algorithm. Bubble sort is a sorting
Classify or segregate array containing even & odd numbers in java (example)
Given an array containing even and odd number in java. We would like to classify the even and odd numbers.
Sort an integer array containing 0 & 1 in java (example)
Given an integer array containing 0 and 1. We would like to sort input array. Zeros will be left end
Check if array contains duplicate elements using java (example)
Problem Statement: Given an array of integer, we would like to find out, whether array contains any duplicate elements. The