Tutorial by Topics: s

Lambda expressions provide a clear and concise way of implementing a single-method interface using an expression. They allow you to reduce the amount of code you have to create and maintain. While similar to anonymous classes, they have no type information by themselves. Type inference needs to happ...

Generics are a facility of generic programming that extend Java's type system to allow a type or method to operate on objects of various types while providing compile-time type safety. In particular, the Java collections framework supports generics to specify the type of objects stored in a collecti...

A layout defines the visual structure for a user interface, such as an activity or widget. A layout is declared in XML, including screen elements that will appear in it. Code can be added to the application to modify the state of screen objects at runtime, including those declared in XML. and...

Arrays allow for the storage and retrieval of an arbitrary quantity of values. They are analogous to vectors in mathematics. Arrays of arrays are analogous to matrices, and act as multidimensional arrays. Arrays can store any data of any type: primitives such as int or reference types such as Object...

An interface is a reference type, similar to a class, which can be declared by using interface keyword. Interfaces can contain only constants, method signatures, default methods, static methods, and nested types. Method bodies exist only for default methods and static methods. Like abstract classes...

The java.util.Map interface represents a mapping between keys and their values. A map cannot contain duplicate keys; and each key can map to at most one value. Since Map is an interface, then you need to instantiate a concrete implementation of that interface in order to use it; there are several M...

Object : An object is an unordered set of name/value pairs. An object begins with { (left brace) and ends with } (right brace). Each name is followed by : (colon) and the name/value pairs are separated by , (comma). Array : An array is an ordered collection of values. An array begins with [...

Strings (java.lang.String) are pieces of text stored in your program. Strings are not a primitive data type in Java, however, they are very common in Java programs. In Java, Strings are immutable, meaning that they cannot be changed. (Click here for a more thorough explanation of immutability.) ...

int read(byte[] b) throws IOException Note that most of the time you do NOT use InputStreams directly but use BufferedStreams, or similar. This is because InputStream reads from the source every time the read method is called. This can cause significant CPU usage in context switches into an...

Default Method introduced in Java 8, allows developers to add new methods to an interface without breaking the existing implementations of this interface. It provides flexibility to allow the interface to define an implementation which will be used as default when a class which implements that inter...

Objects have states and behaviors. Example: A dog has states - color, name, breed as well as behaviors – wagging the tail, barking, eating. An object is an instance of a class. Class − A class can be defined as a template/blueprint that describes the behavior/state that the object of its type suppo...

Note that a ViewTreeObserver instance associated with a View instance can become invalid while that View is still alive. From the View.getViewTreeObserver javadocs: // The returned ViewTreeObserver observer is not guaranteed to remain // valid for the lifetime of this View. If the caller of this...

ParameterDetailsParamsthe type of the parameters sent to the task upon execution.Progressthe type of the progress units published during the background computationResultthe type of the result of the background computation.

All control structures, unless otherwise noted, make use of block statements. These are denoted by curly braces {}. This differs from normal statements, which do not require curly braces, but also come with a stiff caveat in that only the line immediately following the previous statement would b...

SharedPreferences provide a way to save data to disk in the form of key-value pairs. Context Method public SharedPreferences getSharedPreferences(String name, int mode) Activity Method public SharedPreferences getPreferences() SharedPreferences Methods public SharedPre...

Concurrent computing is a form of computing in which several computations are executed concurrently instead of sequentially. Java language is designed to support concurrent programming through the usage of threads. Objects and resources can be accessed by multiple threads; each thread can potentiall...