Read write file using BufferedReader & BufferedWriter in java (example)
BufferWriter, writes to character based stream and BufferReader, reads from character based stream, so as to provide efficient writing/reading of […]
Core Java
Read/write file contents in java (example/InputStreamReader/OutputStreamWriter)
Read & Write file in java using InputStreamReader & OutputStreamWriter class. We will write contents to a file using OutputStreamWriter
Read & write file in java (FileInputStream/ FileOutputStream/ example)
Create or write file in java using FileOutputStream class. FileOutputStream writes the contents to file as stream of bytes. The
Program – simulate or generate unchecked exceptions (java & examples)
1. What is unchecked exception in java? Unchecked exceptions are not checked at compiled time. The unchecked exceptions are not forced
Difference b/w checked & unchecked exception (class hierarchy & example)
Difference between checked and unchecked exceptions in java. Discuss the exception class hierarchy showing checked & unchecked exception in java.
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
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.
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
Convert object having date to/from JSON in java (Jackson ObjectMapper example)
Given the user defined object or POJO having date field, we would like to serialize the POJO to JSON. During serialization, we
Convert list of objects to/from JSON in java (jackson objectmapper/ example)
Given a list of user defined objects, we would like to convert list of pojo objects to JSON (and JSON to list
Convert Array of Objects to / from JSON – Jackson ObjectMapper
Given an array of user defined objects, we would like to convert array of object to JSON and JSON to array
Convert Map to/from JSON string in java (jackson objectmapper/ example)
Given Map of String & object (Map<String,Object>), we would like to convert Map to/from JSON. We will use the jackson’s objectmapper to serialize
Convert object to/from json string in java (jackson objectmapper-example)
Given user defined object in java. Serialize deserialize POJO to JSON string – jackson objectmapper i.e. convert data members of object to json string.
Convert list of objects to /from map in java 8 lambda stream (example)
Given the list of objects, convert list of objects to map. We will use lambda streams to convert list objects
Initialize & loop one, two, three dimensional array in java (example)
Initialize One, Two & Three dimensional array in java. Create & print or loop/iterate static & dynamic multi-dimensional array in java (example).
Date serialization & deserialization – POJO to JSON (GSON & example)
Given the user defined object or POJO, having Date field, we would like to serialize the POJO to JSON. During serialization, we would
Serialize/ convert list of objects to/from json in java (Gson & example)
Given an list of user defined objects, we would like to convert list of pojo objects to JSON (and JSON to list
Convert /Serialize array of objects to / from json in java (Gson /example)
Given an array of user defined objects , we need to convert array of POJOs to JSON String. Also, we will convert
Serialize /Convert Map of object to/from JSON in java (GSON /example)
Given the Map of String and object (Map<String,Object>), we would like to convert Map to JSON and vice versa. We will use the
Read a file line by line using java 8 lambda stream (example)
1. Read file using java 8 lambda stream Given a file, read input file by line by line using lambda