No compiler is provided in this environment

Installed JRE - JDK Selection Eclipse

No compiler is provided in this environment. Perhaps you are running on a JRE rather than a JDK? Failed to execute goal org.apache.maven.plugins:maven-compiler-plugin:3.8.0:compile (default-compile) on project <project-name>: Compilation failure No compiler is provided in this environment. Perhaps you are running on a JRE rather than a JDK? Solution Go to Windows –> Preferences –> Java […]

Java compiler level does not match the version of the installed Java project facet

Java compiler level does not match the version of the installed Java project facet

Java compiler version and project facet selected java version not matching. So we need to change java project facets version according java compiler. Solution Change java project facets java version according java compiler. Select Project –> Right Click –> Project Facets –> Select version in version drop down.

Cannot refer to the non-final local variable productname defined in an enclosing scope

Eclipse Java Compiler

Probably you are using java 8 and the other computer is using java 7. Java requires references to variables from inner classes to be final variables. Java 8 will make them effectively final if you don’t reassign. Probably you are using java 8 and the other computer is using java 7. Java requires references to […]

Arrays

Arrays Class This Class Present in java.util package. It defines several utility methods applicable for arrays. Sorting the elements of Arrays:-Arrays class defines the following three methods to perform sorting. Public static void sort(Primitive[] p) to sort the elements of primitive array, according to natural sorting order. Public static void sort(Object[] o) to sort the […]

Collections

Collections It is an utility class present in java.util package. It defines several utility methods for collection implemented class object. Sorting a list public static void sort(List l), to sort the elements of List, according to natural sorting order. In this case compulsory Objects should be Homogeneous & comparable otherwise we will get ClassCastException. The […]

Enhancement 1.6 version

Enhancement Sun people introduces, the following 2 interface in 1.6 version as the part of collection Framework. 1) NavigableSet 2) NavigableMap. NavigableSet It is the child interface of SortedSet, which defines several methods to support navigation. Ceiling(e): It returns the lowest element, which is greater than equal to e. Higher(e): Returns the lowest element which […]

Queue 1.5 version

Queue This interface has introduced in 1.5 version. If we want to represent, group of Objects Prior to processing, then we should go for Queue. In general Queue follow FIFO, but we can customize based on our requirement. *image* From 1.5 version on wards linkedList also implement Queue interface. LinkedList implementation of Queue always follows […]

Properties

Properties It is the child class of Hashtable. In this case both key and value should be String Object only. Constructor Properties p = new Properties () Important methods of Properties String getProperty (String name). Return the value associated with the specified Property. If the specified property is not available then we will get null. […]

WeakHashMap

WeakHashMap It is exactly same as HashMap, except the following difference. In the case of HashMap, an object is not eligible for garbage, if it is associated with HashMap, even though it doesn’t contain any external reference. i.e HashMap dominates garbage collector. But in the case of WeakHashMap, if an object is not having any […]