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 vote223 views2 answers
Eval javascipt
Java
0 vote218 views1 answer
How to count an replace string in java
Java
1 vote244 views1 answer
Linear layout background color
Java
0 vote221 views1 answer
Initialize empty dictionary java
Java
2 votes208 views1 answer
Error: package android.support.v4.content does not exist import android.support.v4.content.FileProvider; ^
Java
1 vote211 views6 answers
Convert java to python
Java
0 vote221 views2 answers
7877777777777777777777777
Java
13 votes227 views2 answers
Java stringbuilder set value
Java
0 vote252 views1 answer
Spring mvc aop transaction management
Java Spring
1 vote247 views1 answer
Java if or
Java