This video provides a practical demonstration of setting up a Java programming environment, writing, compiling, and executing simple Java programs. It covers configuring environment variables, using a text editor like Notepad++, understanding the compilation and execution process using javac and java commands, and demonstrates examples with basic programs, including array manipulation and a 3D array.
JAVA_HOME and PATH..java extension, compiling it into bytecode using javac, and then executing the bytecode using the java command.System.out.println() for output, string concatenation, and the declaration, initialization, and traversal of 1D and 3D arrays.Introduction:
This lecture provides a practical demonstration of the essential steps involved in Java programming, building upon the theoretical concepts discussed previously. We will cover environment setup, writing and executing simple programs, and working with arrays.
I. Setting Up the Java Development Environment:
JAVA_HOME:
JavaHomeC://Program Files/Java/JDK 1.8.0_171).Path Variable:
bin directory of your JDK installation to the existing Path variable. This is typically done by referencing JAVA_HOME: %JAVA_HOME%\bin. This ensures that Java commands (like javac and java) are accessible from any directory.CLASSPATH Variable (Optional but recommended):
CLASSPATH to point to the bin directory as well: C://Program Files/Java/JDK 1.8.0_171/bin. This helps the Java runtime find class files.II. The Java Program Development Cycle:
FirstJavaProgram.java
public class FirstJavaProgram {
public static void main(String[] args) {
System.out.println("Congratulations your first Java program run successfully.");
}
}
.java extension.FirstJavaProgram, the file must be named FirstJavaProgram.java..java file.javac):
javac YourProgramName.java
javac FirstJavaProgram.java.class file (bytecode) will be generated in the same directory (e.g., FirstJavaProgram.class).FirstJavaProgram1) does not match the file name (FirstJavaProgram.java), compilation will fail.java):
java YourClassName
.class extension here.java FirstJavaProgramIII. Demonstrations of Simple Java Programs:
HelloWorld.java:
System.out.println() to display text.+) within a single println() statement.System.out.println("Your message here"); displays text and moves to the next line. System.out.print("Your message here"); displays text without moving to the next line.TestArray.java (1D Array):
int[] a = {10, 20, 30, 40, 50};a.length returns the number of elements in the array.for loop is used to iterate through the array elements using their indices (starting from 0).println() and print() for controlling output display and adding spaces for better readability.3DArray.java (3D Array):
int[][][] my3DArray = new int[3][4][5];
for loops (three levels deep) to assign values to each element. The value assigned is often a calculation based on the indices (e.g., i * j * k).for loops to iterate through and print the elements. Output is formatted to show the structure of the 3D array as a collection of 2D arrays.IV. Next Steps: