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

2 votes323 views1 answer
How does multiplication works in Java
Java
1 vote302 views1 answer
Java jackson cast to list
Java
0 vote329 views1 answer
Are strings modifiable
Java
7 votes276 views2 answers
Java resource file
Java
0 vote308 views1 answer
Prepared statement update
Java
1 vote284 views1 answer
Java isolate the numbers from string
Java
0 vote319 views1 answer
Initialize linked list in java
Java
2 votes292 views1 answer
Java get jar execution directory
Java
3 votes349 views1 answer
How to make int array java android
Java
7 votes285 views3 answers
How to copy array in java
Java