Java

URL: https://www.progressiverobot.com/java-convert-string-to-double/ Java String to double conversion can be done by many ways. Today we will look into some common ways to convert java string to double primitive data type or Double object. Note that since java supports autoboxing, double primitive type and Double object can be used interchangeably without any issues. Double d1 = […]

URL: https://www.progressiverobot.com/java-futuretask-example-program/ Sometime back I wrote a post about [Java Callable Future](/community/tutorials/java-callable-future-example) interfaces that we can use to get the concurrent processing benefits of threads as well as they are capable of returning value to the calling program. FutureTask is base concrete implementation of Future interface and provides asynchronous processing. It contains the methods to […]

URL: https://www.progressiverobot.com/java-lang-nullpointerexception/ java.lang.NullPointerException is one of the most popular [exceptions in java](/community/tutorials/exception-handling-in-java) programming. Anybody working in java must have seen this popping out of nowhere in the java standalone program as well as the [java web application](/community/tutorials/java-web-application-tutorial-for-beginners). java.lang.NullPointerException NullPointerException is a runtime exception, so we don’t need to catch it in the program. NullPointerException is raised in an […]

URL: https://www.progressiverobot.com/java-randomaccessfile-example/ Java RandomAccessFile provides the facility to read and write data to a file. RandomAccessFile works with file as large [array of bytes](/community/tutorials/string-byte-array-java) stored in the file system and a cursor using which we can move the file pointer position. Java RandomAccessFile !Java RandomAccessFile, RandomAccessFile in java, Java RandomAccessFile read write append example RandomAccessFile […]

URL: https://www.progressiverobot.com/java-spliterator/ Java Spliterator is one of the four iterators – Enumeration, [Iterator](/community/tutorials/java-iterator), [ListIterator](/community/tutorials/java-listiterator) and Spliterator. Java Spliterator Like Iterator and ListIterator, Spliterator is a Java Iterator, which is used to iterate elements one-by-one from a [List](/community/tutorials/java-list) implemented object. Some important points about Java Spliterator are: Java Spliterator is an interface in [Java Collection](/community/tutorials/collections-in-java-tutorial) API. […]

URL: https://www.progressiverobot.com/java-thread-wait-notify-and-notifyall-example/ The Object class in java contains three final methods that allows threads to communicate about the lock status of a resource. These methods are wait(), notify() and notifyAll(). So today we will look into wait, notify and notifyAll in java program. wait, notify and notifyAll in Java ![wait and notify in java, wait […]

URL: https://www.progressiverobot.com/log4j-levels-example-order-priority-custom-filters/ If you have used log4j, you will notice that there are many methods to log messages. For example: logger.trace("My Log message"); logger.debug("My Log message"); logger.info("My Log message"); Actually they corresponds to log4j levels. Log4j Levels Log4j provides many logging levels. Below is the complete list. TRACE: The TRACE Level designates finer-grained informational events […]

URL: https://www.progressiverobot.com/regular-expression-in-java-regex-example/ Welcome to Regular Expression in Java. It's also called Regex in Java. When I started programming, java regular expression was a nightmare for me. This tutorial is aimed to help you master Regular Expression in Java. I will also come back here to refresh my Java Regex learning. Regular Expression in Java ![Regular […]