Use `Integer.parseInt(String s)` for primitive `int`
Use `Integer.valueOf(String s)` for `Integer` object
Use `Long.parseLong(String s)` for `long`
Use `Double.parseDouble(String s)` for `double`
Use `Float.parseFloat(String s)` for `float`
Use `Short.parseShort(String...
Use `Integer.parseInt("123")`
Use `Integer.valueOf("123")`
Use `new Integer("123")`
Use `Integer.parseInt(str.trim())` for strings with surrounding spaces
Use `Integer.parseInt(str, 10)` for base-10 conversion
Use `Integer.parseInt(str, radix)` for other number bases
Use `try-catch` to...
Use `Integer.parseInt("123")`
Use `Integer.valueOf("123")`
Use `new Integer("123")` if needed, though it is deprecated
Use `Integer.parseInt(str.trim())` for strings with surrounding spaces
Use `Integer.parseInt(str, radix)` for numbers in a specific...
Import the Scanner class: `import java.util.Scanner;`
Create a Scanner object: `Scanner sc = new Scanner(System.in);`
Read a string: `String text = sc.nextLine();`
Read a single word: `String...
Open a terminal or command prompt
Type `java -version`
Press Enter
Check the version shown in the output
To check the compiler version, type `javac -version`
Press Enter
Check the...
Create an object of the class
Use the object name followed by a dot and the method name
Pass any required arguments inside parentheses
Call a static...
Install Java
Open a terminal or command prompt
Go to the folder containing the JAR file
Run `java -jar filename.jar`
Replace `filename.jar` with the actual JAR name
If needed,...
Check your current Java version
Open the Java Control Panel or use the terminal
Download the latest Java version from the official Oracle or OpenJDK website
Run...
Download the Java Development Kit (JDK) from Oracle, OpenJDK, or a trusted vendor
Choose the installer for your operating system
Run the installer and follow the...
Download the Java installer from the official Oracle website or install OpenJDK from a trusted source
Run the downloaded installer
Follow the on-screen installation prompts
Accept the...
Install the Java Development Kit (JDK)
Set up your development environment
Create a Java source file with the `.java` extension
Write a class definition
Add the `main` method
Write...
Use `Scanner` and `nextLine()`
Use `BufferedReader` and `readLine()`
Use `Console` and `readLine()`
Use `Scanner` and `next()`
Use `BufferedInputStream` with custom parsing
Use `JOptionPane.showInputDialog()`
Use `args` for command-line input
Use `System.setProperty("java.library.path", "path/to/dir")`
Use `System.setProperty("user.dir", "path/to/working/directory")`
Use `new File("path/to/file")` for relative or absolute file paths
Use `Paths.get("path", "to", "file")` for platform-independent paths
Use `Path path = Path.of("path", "to",...
Install the Java Development Kit (JDK)
Open Command Prompt
Check Java installation with `java -version`
Check compiler installation with `javac -version`
Navigate to the folder containing the `.java`...
Use a two-pointer approach with `start` and `end`
Swap elements at `start` and `end`
Increment `start`
Decrement `end`
Repeat until `start < end`
Example:
`int arr = {1, 2, 3,...
Make the constructor `private`
Declare a `private static` instance of the class
Provide a `public static` method to return the instance
Use lazy initialization if you want...
Install the JDK and set up an IDE
Learn Java syntax and basic program structure
Practice variables, data types, and operators
Study control flow with if, switch,...
Open Command Prompt or Terminal
Type `java -version`
Press Enter
If Java is installed, version details will appear
If Java is not installed, an error message will appear
Type...
Declare a private static instance of the class
Make the constructor private
Provide a public static method to return the instance
Initialize the instance eagerly or lazily
Use...
Use `Character.getNumericValue(ch)` for numeric characters and many Unicode digits
Use `ch - '0'` for digit characters `'0'` to `'9'`
Use `Integer.parseInt(String.valueOf(ch))` for a single digit character
Use...
Use direct cast: `(int) ch`
Use `Character.getNumericValue(ch)` for digit characters and some letters
Use `Character.digit(ch, 10)` for base-10 digit characters
Use arithmetic with `'0'`: `ch - '0'`...
Install the Java Development Kit (JDK)
Open Command Prompt
Check Java installation with `java -version`
Check compiler installation with `javac -version`
Navigate to the folder containing the `.java`...
Use `str1.equals(str2)` for exact content comparison
Use `str1.equalsIgnoreCase(str2)` for case-insensitive comparison
Use `str1.compareTo(str2)` for lexicographic comparison
Use `str1.compareToIgnoreCase(str2)` for case-insensitive lexicographic comparison
Use `Objects.equals(str1, str2)` for null-safe comparison
Use...
Use `str1.equals(str2)` for case-sensitive content comparison
Use `str1.equalsIgnoreCase(str2)` for case-insensitive content comparison
Use `str1.compareTo(str2)` to compare lexicographically
Use `str1.compareToIgnoreCase(str2)` to compare lexicographically without case sensitivity
Use `==` only...
Open Command Prompt or Terminal
Type `java -version`
Press Enter
If Java is installed, the version information will appear
If Java is not installed, an error message will...
Open Command Prompt or Terminal
Type `java -version`
Press Enter
If Java is installed, the version details will appear
If Java is not installed, an error message will...
Use a fixed-size array and assign values by index
Declare and initialize an array with values directly
Create a new larger array and copy old elements...
Use `Collections.sort(list);` for natural ordering
Use `list.sort(Comparator.naturalOrder());` for natural ordering
Use `list.sort(Comparator.reverseOrder());` for reverse ordering
Use `Collections.sort(list, comparator);` for custom sorting
Use `list.sort((a, b) -> a.compareTo(b));` for custom...
Use `Collections.sort(list);`
Use `list.sort(Comparator.naturalOrder());`
Use `list.sort(Comparator.reverseOrder());`
Use `Collections.sort(list, Comparator.comparing(...));`
Use `list.sort((a, b) -> a.compareTo(b));`
Use `list.sort((a, b) -> b.compareTo(a));`
Use `list.sort(Comparator.comparingInt(...));`
Use `list.sort(Comparator.comparing(...).reversed());`
Open Eclipse
Go to Help
Select Eclipse Marketplace
Search for Maven Integration for Eclipse
Install the Maven plugin if it is not already installed
Restart Eclipse
Go to Window
Select Preferences
Expand...
