Types of generics in java

Java generic type method

// generic methods

public <T> List<T> fromArrayToList(T[] a) {   
	    return Arrays.stream(a).collect(Collectors.toList());
	}

public static <T, G> List<G> fromArrayToList(T[] a, Function<T, G> mapperFunction) {
	    return Arrays.stream(a)
	      .map(mapperFunction)
	      .collect(Collectors.toList());
	}

// bounded generics

public <T extends Number> List<T> fromArrayToList(T[] a) {
	    ...
	}

//multiple bounds

<T extends Number & Comparable>

// upper bound wildcards

public static void paintAllBuildings(List<? extends Building> buildings) {
	    ...
	}
    
// lower bound wildcard

<? super T>

Source: baeldung.com

Java generics type

Java Generic Type Naming convention helps us understanding code easily and having a naming convention is one of the best practices of Java programming language. So generics also comes with its own naming conventions. Usually, type parameter names are single, uppercase letters to make it easily distinguishable from java variables. The most commonly used type parameter names are:

E – Element (used extensively by the Java Collections Framework, for example ArrayList, Set etc.)
K – Key (Used in Map)
N – Number
T – Type
V – Value (Used in Map)
S,U,V etc. – 2nd, 3rd, 4th types

Source: grepper.com

Similar codes

0 vote174 views1 answer
Ejercicios java clases abstractas
Java
-1 vote185 views1 answer
Java string swap two characters
Java
0 vote206 views1 answer
Class BuildConfig is public, should be declared in a file named BuildConfig.java
Java
3 votes223 views2 answers
Java scanner string nextline after nextint
Java
0 vote207 views1 answer
Java remote debug
Java
0 vote199 views2 answers
My maven project give error when adding javax.xml.bind dependency
Java
0 vote231 views2 answers
Detect bluetooth headphones android programmatically
Java
124 votes518 views6 answers
How to create a random number in java
Java
2 votes218 views2 answers
Android java display icon in action bar
Java
3 votes191 views1 answer
How to create textview programmatically in android
Java