Java 中有趣又酷的小技巧
Java 是最好的面向对象编程语言之一，由詹姆斯·高斯林于 1991 年从太阳微系统公司开发，并于 1995 年公开发行。它是一种解释型编程语言，具有平台独立性，是所有编程语言中最好的一种。
在本文中，我们将看到 Java 中一些有趣且很酷的技巧。
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Executing Comments: Most of the developers think comments are never executed in a program and are used for ease in understanding the code. But, they are executed. For example:
java public class GFG { public static void main(String[] args) { // \u000d System.out.println("GeeksForGeeks"); } }Output:
```java GeeksForGeeks
```
解释: 这个注释是因为 unicode 字符“\u000d”而执行的，java 编译器将这个 Unicode 字符解析为一个新行。Java 允许使用 Unicode 字符而不编码。
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Underscore in Numeric Literals: In Java SE 7 and above, underscores can be used in numeric literals without generating any warning or error in the output.
示例:
java public class GFG { public static void main(String[] args) { int x = 123_34; System.out.println(x); } }Output:
```java 12334
```
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Double Brace Initialization: In Java, collections such as sets, lists, maps, etc. does not have a simple and easy way to initialize the values during declaration. Developers either push values into the collection or creates a static block for the constant collection. Using double brace initialization, collections can be initialized during declaration with less efforts and time.
示例:
```java import java.util.HashSet; import java.util.Set;
public class GFG { public static void main(String[] args) { Set GFG = new HashSet() {{ add("DS"); add("ALGORITHMS"); add("BLOCKCHAIN"); add("MACHINE LEARNING"); } }; System.out.println(GFG); } } ```
Output:
```java [MACHINE LEARNING, ALGORITHMS, DS, BLOCKCHAIN]
```
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Finding a position to insert the numeric element in the array: There is a small cool trick to find the position where the requested element can be inserted in the sorted array.
示例:
```java import java.util.Arrays; public class GFG { public static void main(String[] args) { int[] arr = new int[] { 1, 3, 4, 5, 6 };
// 2 has to be inserted int pos = Arrays.binarySearch(arr, 2); System.out.print("Element has to be inserted at: " + ~pos); } } ```
Output:
```java Element has to be inserted at: 1
```
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包装类 vs 数据类型:在下面的示例中，第二个 print 语句不会显示 true，因为包装类对象的引用正在被比较，而不是它们的值。
```java import java.util.Arrays; public class GFG { public static void main(String[] args) { int num_1 = 10;
int num_2 = 10;
Integer wrapnum_1 = new Integer(10);
Integer wrapnum_2 = new Integer(10);
System.out.println(num_1 == num_2);
// Compares reference System.out.println(wrapnum_1 == wrapnum_2);
// Compares value of object System.out.println(wrapnum_1.equals(wrapnum_2)); } } ```
输出:
```java true false true
```
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