public class TestArrayToLinkedList
1: //TestArrayToLinkedList.java
2: //Illustrates the conversion of an array to an LinkedList.
3: //Also illustrates some variations on how to create arrays
4: //and how to process an LinkedList once it has been created
5: //from an array.
7: import java.util.LinkedList;
8: import java.util.Arrays;
9: import java.util.stream.Collectors;
10: import java.util.stream.Stream;
12: public class TestArrayToLinkedList
13: {
14: public static void main(String[] args)
15: {
16: System.out.println();
18: //First we create an array of integers, display it, put it into
19: //an LinkedList of Integer, and then display the values again.
20: //Here's one way to create an array of integers:
21: Integer[] integers1 = new Integer[]
22: {
23: 4, 1, 5, 3, 2
24: };
25: System.out.print("integers1: ");
26: for (Integer i : integers1)
27: {
28: System.out.print(i + " ");
29: }
30: System.out.println();
32: //Here's another way (that creates the same array as above):
33: Integer[] integers2 =
34: {
35: 4, 1, 5, 3, 2
36: };
37: System.out.print("integers2: ");
38: for (int i : integers2)
39: {
40: System.out.print(i + " ");
41: }
42: System.out.println();
44: //And now we create an LinkedList from an array, using
45: //the static method Arrays.asList() from the Arrays class:
46: LinkedList<Integer> integerLinkedList =
47: new LinkedList<Integer>(Arrays.asList(integers1));
48: System.out.print("integerLinkedList: ");
49: for (int i : integerLinkedList)
50: {
51: System.out.print(i + " ");
52: }
53: System.out.println("\n");
55: //================================================================
56: //Now we repeat what we did in the above three code segments, but
57: //this time with strings instead of integers:
58: String strings1[] = new String[]
59: {
60: "klm", "abc", "xyz", "pqr"
61: };
62: System.out.print("strings1: ");
63: for (String s : strings1)
64: {
65: System.out.print(s + " ");
66: }
67: System.out.println();
69: String strings2[] =
70: {
71: "klm", "abc", "xyz", "pqr"
72: };
73: System.out.print("strings2: ");
74: for (String s : strings2)
75: {
76: System.out.print(s + " ");
77: }
78: System.out.println();
80: LinkedList<String> stringLinkedList =
81: new LinkedList<>(Arrays.asList(strings1));
82: System.out.print("stringLinkedList: ");
83: for (String s : stringLinkedList)
84: {
85: System.out.print(s + " ");
86: }
87: System.out.println("\n");
89: //================================================================
90: //Now we sort each LinkedList according to the "natural order" of
91: //its elements:
92: integerLinkedList.sort(null); //sort according to "natural order"
93: System.out.print("integerLinkedList sorted: ");
94: for (int i : integerLinkedList)
95: {
96: System.out.print(i + " ");
97: }
98: System.out.println();
100: stringLinkedList.sort(null); //sort according to "natural order"
101: System.out.print("stringLinkedList sorted: ");
102: for (String s : stringLinkedList)
103: {
104: System.out.print(s + " ");
105: }
106: System.out.println();
108: System.out.println();
110: String[] array =
111: {
112: "Hello", "World"
113: };
115: //Create LinkedList from array
116: LinkedList<String> list = new LinkedList<>(Arrays.asList(array));
117: System.out.println(list);
119: //In Java 8 you can use
120: list = Stream.of(array).collect(Collectors.toCollection(LinkedList::new));
121: System.out.println(list);
123: //In Java 9 you can use
124: //List<String> list = List.of("Hello", "World");
125: //System.out.println(list);
126: //Initialization of an LinkedList in one line
127: LinkedList<String> list2 = new LinkedList<String>()
128: {
129: {
130: add("Hello");
131: add("World");
132: }
133: };
134: System.out.println(list2);
136: }
137: }
138: /* Output:
140: integers1: 4 1 5 3 2
141: integers2: 4 1 5 3 2
142: integerLinkedList: 4 1 5 3 2
144: strings1: klm abc xyz pqr
145: strings2: klm abc xyz pqr
146: stringLinkedList: klm abc xyz pqr
148: integerLinkedList sorted: 1 2 3 4 5
149: stringLinkedList sorted: abc klm pqr xyz
151: [Hello, World]
152: [Hello, World]
153: [Hello, World]
154: */