## Java Cheatsheet

## Java Cheatsheet

Java is a general-purpose programming language that is widely used for developing desktop, web, and mobile applications. Here's a quick overview of its unique features and some code blocks for common tasks.

### Variables

Declare variables using the data type followed by the variable name. Java is a statically typed language, so the data type of a variable cannot be changed after it is declared.

```java
int x = 10;
char c = 'a';
double d = 3.14;
```

### Functions

Functions in Java are declared using the `public static` keywords. They can take parameters and return values.

```java
public static int add(int a, int b) {
return a + b;
}
```

### Loops

Java supports `for`, `while`, and `do-while` loops for iterating over arrays or performing a task a certain number of times.

```java
int[] numbers = {1, 2, 3, 4, 5};

for (int i = 0; i < 5; i++) {
System.out.println(numbers[i]);
}

int i = 0;
while (i < 5) {
System.out.println(numbers[i]);
i++;
}

i = 0;
do {
System.out.println(numbers[i]);
i++;
} while (i < 5);
```

### Conditionals

Use `if` statements to execute code based on a condition. `else if` and `else` statements can be used to handle multiple conditions.

```java
int x = 10;

if (x > 0) {
System.out.println("x is positive");
} else if (x < 0) {
System.out.println("x is negative");
} else {
System.out.println("x is zero");
}
```

### File Manipulation

Java provides built-in support for file manipulation, including reading and writing files, and interacting with the file system.

```java
import java.io.File;
import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Paths;

public class Main {
public static void main(String[] args) {
File file = new File("/path/to/file.txt");

try {
String contents = new String(Files.readAllBytes(Paths.get(file.getAbsolutePath())));
System.out.println(contents);

Files.write(Paths.get(file.getAbsolutePath()), "New contents".getBytes());

if (file.delete()) {
System.out.println("File deleted successfully");
} else {
System.out.println("Error deleting file");
}
} catch (IOException e) {
System.out.println("An error occurred");
e.printStackTrace();
}
}
}
```

### Resources

Here are some resources to help you learn more about Java:

- [Java Tutorials](https://docs.oracle.com/javase/tutorial/index.html)
- [Head First Java](https://www.amazon.com/Head-First-Java-Kathy-Sierra/dp/0596009208) (Book by Kathy Sierra and Bert Bates)
- [Codecademy Java Course](https://www.codecademy.com/learn/learn-java) (Interactive Java tutorial)