Threads are a basic concept in concurrent and parallel programming . They allow programs to do multiple things at the same time and are often used for performing computationally intensive tasks in the background without interrupting the main program. This is accomplished through multithreading, a common programming and execution model which allows multiple threads to exist within the context of one process. These threads share resources but are able to execute independently.

An IllegalMonitorStateException is a runtime exception in Java that occurs in multithreaded applications. It indicates that the calling thread has attempted to wait on an object's monitor, or attempted to notify other threads waiting on an object's monitor, without owning the specified monitor. Since the IllegalMonitorStateException is an unchecked exception, it does not need to be declared in the throws clause of a method or constructor.

With the ongoing release of new technologies in the IT market, your choices for programming languages is also changing. This makes the task of choosing one among all the languages a tough job. Java and.Net are two renowned languages that have been involved in a locked horn competition for years. Since both languages offer unique benefits, opting for one is itself a brainstorming tussle.

Runtime errors occur when a program is being executed and, in the case of compiled languages, after the program has been successfully compiled. Runtime errors are, therefore, harder to detect and prevent than compile-time errors . This allows for a certain category of errors to be captured and dealt with before the program effectively starts.

The NegativeArraySizeException is a runtime exception in Java that occurs when an application attempts to create an array with a negative size. Since the NegativeArraySizeException is an unchecked exception, it does not need to be declared in the throws clause of a method or constructor.

Unlike compile-time errors which are detected during compilation .

An ArrayStoreException is a runtime exception in Java that occurs when an attempt is made to store the incorrect type of object into an array of objects. For example, if an Integer object is attempted to be stored in an String array, a “java.lang.ArrayStoreException: java.lang.Integer” is thrown.

An UnsupportedOperationException is a runtime exception in Java that occurs when a requested operation is not supported. For example, if an unmodifiable List is attempted to be modified by adding or removing elements, an UnsupportedOperationException is thrown. This is one of the common exceptions that occur when working with Java collections such as List, Queue, Set and Map. The UnsupportedOperationException is a member of the Java Collections Framework.

Variables are memory containers used to store information. In Java, every variable has a data type and stores a value of that type. Data types, or types for short, are divided into two categories: primitive and non-primitive. There are eight primitive types in Java: byte, short, int, long, float, double, boolean and char. These built-in types describe variables that store single values of a predefined format and size.

Strings are a fundamental data type in most modern general-purpose programming languages. In Java, strings are defined as character sequences and are represented as immutable objects of the class java.lang.String which contains various constructors and methods for creating and manipulating strings . Below is an example of the string literal "rollbar" being assigned to two different variables a and b which both reference the same (automatically interned) String object.