HowToDoInJava

Java Tutorials

“Core Java” is Sun’s term, used to refer to Java SE, the standard edition and a set of related technologies, like the Java VM, CORBA, etc. This is mostly to differentiate from others like Java ME or Java EE. “Core Java” is Oracle’s definition and refers to subset of Java SE technologies.

The Core Java technologies and application programming interfaces (APIs) are the foundation of the Java Platform, Standard Edition (Java SE). They are used in all classes of Java programming, from desktop applications to Java EE applications.

  1. Java 8 – Period
  2. Java 8 – TemporalAdjusters
  3. Java – Date Formatting
  4. Java 8 – Date Parsing and Validation
  5. Java – Get All Dates Between Two Dates
  6. Java 8 – Calculate days between two dates
  7. Java 8 – Calculate business days between two dates
  8. Java 8 – Add or subtract N business days to date
  9. Java 8 – DayOfWeek
  10. Java 8 – TemporalQuery
  11. Java – Get Next and Previous Date
  12. Java UUID Generator Example
  13. Pairs in Java
  14. Java 8 – Parse string to date-time in UTC
  15. Java 8 ResolverStyle.STRICT
  16. Java DelayQueue
  17. ExecutorService – shutdown(), shutdownNow() and awaitTermination​()
  18. ExecutorService – Cancel a task in executor
  19. ScheduledExecutorService – Running task in executor after delay
  20. ExecutorService invokeAll()
  21. ExecutorService invokeAny()
  22. Callable Future Example
  23. Executor RejectedExecutionHandler
  24. ExecutorService in Java
  25. Compare LocalDateTime instances
  26. Compare LocalDate instances
  27. A Guide to AtomicInteger in Java
  28. Format date/timestamp in 12 hours pattern
  29. LocalDate format() API
  30. Java – Check given year is leap year or not?
  31. Java 8 – Compare ZonedDateTime
  32. Format ZonedDateTime to String in Java 8
  33. Convert between LocalDate and ZonedDateTime
  34. Java 8 – Convert between LocalDateTime and LocalDate
  35. ZonedDateTime parse()
  36. LocalDateTime parse()
  37. LocalDate parse()
  38. Java ZonedDateTime class
  39. Java LocalDateTime class
  40. Java LocalTime class
  41. Java LocalDate class
  42. Java command line arguments
  43. A Guide to Recursion in Java
  44. Java Naming Conventions
  45. Difference between this and super in Java
  46. strictfp modifier in Java
  47. Difference between final, finally and finalize in Java
  48. Java throw and throws keywords
  49. Java synchronized keyword
  50. Java try catch finally blocks
  51. Java boolean keyword
  52. Java assert keyword – assertion in Java
  53. Java abstract keyword – abstract classes and methods
  54. Java Control Flow Statements
  55. Java CopyOnWriteArraySet class
  56. Java CopyOnWriteArrayList class
  57. Java TransferQueue – Java LinkedTransferQueue class
  58. Java ArrayBlockingQueue class
  59. Java PriorityBlockingQueue class
  60. Java PriorityQueue class
  61. Java Spliterator interface
  62. Java ListIterator interface
  63. Java Iterator interface example
  64. Java Comparator interface example
  65. Java Comparable interface example
  66. Java LinkedList class
  67. Java TreeSet class
  68. Java LinkedHashSet class
  69. Java HashSet class
  70. Java Hashtable class
  71. Java TreeMap class
  72. Java LinkedHashMap class
  73. How to clone HashMap – Shallow and Deep Copy
  74. How to remove duplicate elements in ArrayList
  75. How to Synchronize HashMap in Java
  76. How to join or merge two hashmaps in Java
  77. How to compare two hashmaps in Java
  78. ArrayList spliterator() method example
  79. ArrayList removeIf() – remove objects by field
  80. ArrayList sort() – Sort list of objects by field
  81. ArrayList replaceAll() method example
  82. ArrayList retainAll() method example
  83. ArrayList removeAll() – remove all occurrences from list
  84. ArrayList remove() method example
  85. ArrayList listIterator() method example
  86. ArrayList forEach() example – Java 8
  87. ArrayList clone() – ArrayList deep copy and shallow copy
  88. ArrayList clear() – Empty ArrayList in Java
  89. ArrayList addAll() method example
  90. Java tuple – Working with tuples in Java
  91. ArrayList add() method example
  92. Difference between LinkedList vs ArrayList in Java
  93. Difference between ArrayList vs Vector in Java
  94. How to convert HashSet to ArrayList in Java
  95. Convert array to list in Java
  96. How to convert ArrayList to String Array in Java
  97. How to convert LinkedList to ArrayList in Java
  98. How to convert Vector to ArrayList in Java
  99. Java ArrayList toArray() – Convert ArrayList to Array
  100. Java ArrayList contains() – Check if element exists
  101. Java ArrayList ensureCapacity() method example
  102. How to replace existing element in ArrayList
  103. Check if ArrayList is empty or not in Java
  104. Java format string to phone number with dashes – (123) 456-6789 pattern
  105. Get first 4 characters of String in Java
  106. Get last 4 characters of String in Java
  107. How to empty or clear ArrayList in Java
  108. How to merge two ArrayLists in Java
  109. How to serialize and deserialize ArrayList in Java
  110. How to swap two elements in ArrayList in Java
  111. How to synchronize ArrayList in Java
  112. How to compare two ArrayLists in Java
  113. ArrayList get() method – Get element at index from ArrayList
  114. Arraylist indexOf() – Get index of element in arraylist
  115. Arraylist lastIndexOf() – Get last index of element in arraylist in Java
  116. Get sublist of ArrayList – ArrayList subList() method
  117. Add multiple items to ArrayList in Java
  118. How to remove element from ArrayList in Java
  119. ArrayList add/replace element at specified index in Java
  120. How to iterate through ArrayList of objects in Java
  121. How to initialize ArrayList in Java
  122. Java String intern() method example
  123. Java String contains() method example
  124. Java String toLowerCase() method example
  125. Java String toUpperCase() method example
  126. Java String split() method example
  127. Java String replaceAll() method example
  128. Java String replaceFirst() method example
  129. Java String replace() method example
  130. Java String concat() method example
  131. Java String substring() method example
  132. Java String lastIndexOf() method example
  133. Java String indexOf() method example
  134. Java String hashCode() method example
  135. Java String endsWith() method example
  136. Java String startsWith() example
  137. Java String compareToIgnoreCase() method example
  138. Java String compareTo() method example
  139. Java String equalsIgnoreCase() method – Case-insensitive comparison
  140. Java String equals() method – Java compare strings
  141. Java String charAt() method example
  142. Java – Find duplicate characters in String
  143. Java hashCode() and equals() – Contract, rules and best practices
  144. Java convert float to String – Format to N decimal points
  145. Java StackTrace to String Example
  146. Java – Right pad a string with spaces or zeros
  147. Java – Left pad a string with spaces or zeros
  148. Java 8 StringJoiner Example
  149. Java remove extra white spaces between words in String
  150. Java remove leading whitespaces from String
  151. Java remove trailing whitespaces from String
  152. Java reverse string using recursion
  153. Reverse words in string in Java
  154. Convert long to String in Java
  155. Convert String to Long in Java
  156. Convert int to String in Java
  157. Java wrapper classes – autoboxing, unboxing and conversion examples
  158. Convert String to Title Case in Java
  159. Java Unescape HTML to String Example
  160. Java Escape HTML – Encode String to HTML Example
  161. Duration or difference between two dates
  162. Java 8 DateTimeFormatter
  163. Convert between LocalDate to java.sql.Date
  164. Convert between LocalTime to java.sql.Time
  165. Java – Convert Date to LocalDate
  166. Java – Convert Date to LocalDateTime
  167. Java 8 – Convert between LocalDateTime and ZonedDateTime
  168. Java timezone conversion example
  169. Java add days to Date and LocalDateTime
  170. Java format LocalDateTime to String
  171. Java – Measure elapsed time
  172. Java Convert String to LocalDate
  173. Java parse String to Date
  174. Java – Get Current Timestamp
  175. Java – Date Comparison
  176. Java convert date to EST/EDT timezone
  177. Create List with Single Element
  178. Java – Append to File
  179. Java – Write to File
  180. Java Comments
  181. Java variables
  182. What is Java JDK, JRE and JVM – In-depth Analysis
  183. Java Garbage Collection Algorithms [till Java 9]
  184. Java – Read typesafe input using Scanner class
  185. Correct way to compare floats or doubles in Java
  186. Java Static – Variable, Method, Block, Class and Import Statement
  187. Java Read File to String [Updated for Java 8]
  188. Convert Java String to int
  189. Java enum with string values
  190. Java Split CSV String – Convert String to List Example
  191. Java custom serialization using readObject and writeObject
  192. Convert XMLGregorianCalendar to date time – Format to string
  193. Format XMLGregorianCalendar to ‘MM/dd/yyyy hh:mm a z’ pattern
  194. Java Iterate List Examples
  195. Java – Convert OutputStream to InputStream Example
  196. Java Locale – Create and Set Default Locale
  197. Java – Unzip File with Sub-directories
  198. Java – Get Current Working Directory Example
  199. Serialize Java Object to XML – XMLEncoder and XMLDecoder Example
  200. Difference between Externalizable vs Serializable in Java
  201. Java Externalizable Example – More Efficient Serialization
  202. Generate Random Numbers Example in Java
  203. Java classpath
  204. Read file from resources folder – Spring Example
  205. How to read file in java
  206. Producer Consumer Problem Using BlockingQueue
  207. Different ways to iterate over Collections in Java
  208. Binary, Octal, and Hexadecimal Conversions in Java
  209. Java Thread Life Cycle and Thread States
  210. Concurrency vs. Parallelism
  211. Java System Properties
  212. Java Date – parse, format and conversion
  213. Java – Current date & time
  214. Java Multi-threading Evolution and Topics
  215. Difference between lock and monitor – Java Concurrency
  216. Java 8 Difference Between Two Dates
  217. Is enum Really Best Singletons?
  218. Difference between enumerator and iterator?
  219. How Iterator works in java
  220. Java – Create Password Protected Zip File
  221. Left, right, or center align string in Java
  222. Static Import Declarations in Java
  223. Java create class – how to create objects?
  224. Continue keyword / statement in Java
  225. Java break keyword
  226. do-while loop in Java
  227. while loop in Java
  228. Java for-each loop | enhanced for-each loop example
  229. for loop in Java
  230. Switch Statement in Java
  231. if-else statement in Java
  232. What is Block Statement in Java
  233. Types of Statements in Java
  234. A guide to Java Operators
  235. Little-Endian and Big-Endian in Java
  236. Data Types in Java
  237. What is Java programming language?
  238. Primitive Data Types in Java
  239. ScheduledThreadPoolExecutor – Task Scheduling with Executors
  240. Java Callable Future Example
  241. Java Fixed Size Thread Pool Executor Example
  242. Java Thread Pool – ThreadPoolExecutor Example
  243. ConcurrentLinkedDeque Example – Non-blocking Thread-safe List
  244. How to Copy Directories in Java
  245. Generate SHA or MD5 file checksum hash in java
  246. Java Create Read Only File Example
  247. Java File Copy – 4 Ways to Copy Files in Java
  248. Java FilenameFilter Example – Find/delete files of certain extension
  249. Java – BufferedWriter
  250. Java BufferedReader Example
  251. Java – Create New File
  252. Control concurrent access to multiple copies of a resource using Semaphore
  253. How to work with wait(), notify() and notifyAll() in Java?
  254. Binary Semaphore Tutorial and Example
  255. How to Use Locks in Java | java.util.concurrent.locks.Lock Tutorial and Example
  256. Creating Threads Using java.util.concurrent.ThreadFactory
  257. Java ThreadLocal Variables – When and How to Use?
  258. How to Restart Thread Using UncaughtExceptionHandler
  259. How Java I/O Works Internally at Lower Level?
  260. Java – Delete Temporary File
  261. Java – Create Temporary File
  262. Java – Write to Temporary File
  263. How to check if file exists in Java
  264. Convert String to InputStream in Java
  265. Java read file to byte[] array
  266. Java – Read Write UTF-8 Encoded Data
  267. JVM Memory Model / Structure and Components
  268. Java – Read File Line by Line – LineNumberReader
  269. Java Read and Write Property File Example
  270. Java – Read console input
  271. Java FileFilter Example
  272. Location Based Currency Formatting in Java
  273. Java – Get Current User Locale
  274. How Deserialization Process Happen in Java?
  275. Java Generics PECS – Producer Extends Consumer Super
  276. Java transient keyword example
  277. Difference between 32-bit java vs. 64-bit java
  278. Complete Java Generics Tutorial
  279. Java Compare and Swap Example – CAS Algorithm
  280. Java Reflection – Real Usage Examples
  281. Complete Java Annotations Tutorial
  282. Difference between HashMap vs Hashtable in Java
  283. Convert Hex to ASCII and ASCII to Hex
  284. Java Concurrency – Difference between yield() and join()
  285. Java Concurrency – Thread Safety?
  286. Java split string – Java tokenize string examples
  287. Difference between java.exe and javaw.exe
  288. Java calculate age from date of birth
  289. Throttling Task Submission Rate with ThreadPoolExecutor and Semaphore
  290. Delete directory recursively in Java
  291. Java Standard IO vs. Java NIO
  292. JDBC Performance Optimization Tips
  293. Java JDBC PreparedStatement Example
  294. JDBC SQL DELETE Query Example
  295. JDBC SQL INSERT Query Example
  296. JDBC SELECT Query Example
  297. Java – JDBC Connection Example (MySQL)
  298. Java – JDBC Driver Types
  299. Java Checked vs Unchecked Exceptions
  300. Labeled Statements in Java
  301. Instanceof operators don’t need explicit null checks
  302. Checked exceptions thrown in initializer blocks can be declared by the constructors
  303. Usage of class sun.misc.Unsafe
  304. Java serialVersionUID – How to generate serialVersionUID
  305. Convert InputStream to String In Java
  306. Why Strings are Immutable in Java?
  307. Java View/Generate Bytecode of Class File
  308. Java concurrency – CountDownLatch Example
  309. Top 40 Java collection interview questions and answers
  310. Parse CSV files in java
  311. Java ConcurrentHashMap Best Practices
  312. [Solved] java.lang.IncompatibleClassChangeError: Implementing class
  313. How to design good custom key object for HashMap
  314. Java NullPointerException – How to effectively handle null pointer in Java
  315. Use Array instead of Vector.elementAt() for Better Performance
  316. Performance Comparison of Different Ways to Iterate over HashMap
  317. Always Use length() Instead of equals() to Check Empty String
  318. Performance Comparison – Different For Loops in Java
  319. Java executor framework tutorial and best practices
  320. Difference between Runnable vs Thread in Java
  321. Difference between sleep() and wait() in Java
  322. Object level lock vs Class level lock in Java
  323. Java Wrapper Classes Internal Caching
  324. Java Pass-by-Value vs. Pass-by-Reference
  325. Java Strict Date Validation – Java SimpleDateFormat setLenient() Method
  326. Java puzzle – Why try-catch-finally blocks require braces?
  327. Java enum
  328. Java synchronous and asynchronous exceptions
  329. Java deep copy using in-memory serialization
  330. Java Serialization – Dos and don’ts for correct serialization
  331. Java Double Brace Initialization
  332. Java Inter-thread Communication – PipedReader and PipedWriter
  333. Java Memory Management – Garbage Collection Algorithms
  334. Java Cloneable interface – Is it broken?
  335. How to Find Duplicate Words in String in Java
  336. Java clone – deep and shallow copy – copy constructors
  337. Java Custom Exceptions – Best Practices
  338. Java main() method
  339. finalize() Method in Java – Why you should not use it?
  340. How to create immutable class in Java
  341. Java String Interview Questions with Answers
  342. Java ThreadPoolExecutor and BlockingQueue Example
  343. Java Deadlock Example and Solution
  344. How HashMap works in Java