We can declare, initialize and add value in List and ArrayList in single line in following ways -
Example - To declare, Initialize and add value in ArrayList in single line.
import java.util.ArrayList;
public class InitialzeArrayListInOneLine {
public static void main(String[] args) {
ArrayList<String> arrayList = new ArrayList<String>() {{
add("a");
add("b");
add("c");
}};
}
}
|
Here we took just 1 line to declare, initialize ArrayList and add 3 values in it using Anonymous inner class.
Without Anonymous inner class / double brace initialization above code will be written in many lines >
import java.util.ArrayList;
public class InitialzeArrayListInOneLine {
public static void main(String[] args) {
ArrayList<String> list = new ArrayList<String>();
list.add("a");
list.add("b");
list.add("c");
}
}
|
Here we took 4 lines to declare, initialize array and add 3 values in it.
2) Using Arrays.asList method >
Example - To Initialize and add value in List in single line.
import java.util.Arrays;
import java.util.List;
public class InitialzeArrayListInOneLine {
public static void main(String[] args) {
List<String> list = Arrays.asList("a", "b", "c");
}
}
|
Here we took just 1 line to declare, initialize list and add 3 values in it using Anonymous inner class.
Summary >
So, in this tutorial we did following >
1) Anonymous inner class / double brace initialization to declare, Initialize and add value in ArrayList in single line.
ArrayList<String> arrayList = new ArrayList<String>() {{
add("a");
add("b");
add("c");
}};
}
|
2) And Arrays.asList to declare, Initialize and add value in List in single line.
List<String> list = Arrays.asList("a", "b", "c");
|
Inner class/ nested class, static, local and anonymous inner class in java
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ArrayList in java
LinkedList in java
Set >
HashSet in java
Map >
HashMap in java
Labels:
Core Java