Variables in Logo

In Java, variables are explicitly declared and used by the compiler to check type-correctness of method calls.

public class Variables {
    public static void main(String[] args) {
        // String variable declaration and initialization
        String a = "initial";
        System.out.println(a);

        // You can declare multiple variables of the same type at once
        int b = 1, c = 2;
        System.out.println(b + " " + c);

        // Java will infer the type of initialized variables when using var (Java 10+)
        var d = true;
        System.out.println(d);

        // Variables declared without initialization are given default values
        // For example, the default value for an int is 0
        int e;
        System.out.println(e);

        // In Java, we don't have a direct equivalent to Go's := syntax
        // But we can declare and initialize in one line
        String f = "apple";
        System.out.println(f);
    }
}

To run this program:

$ javac Variables.java
$ java Variables
initial
1 2
true
0
apple

In Java, variables are declared with a specific type, or using the var keyword for local variable type inference (introduced in Java 10). Unlike Go, Java doesn’t have a shorthand := syntax for declaration and initialization.

Variables in Java are explicitly typed, and the compiler uses this information to ensure type safety. When a variable is declared without initialization, it’s given a default value based on its type (e.g., 0 for int, false for boolean, null for object references).

Java also allows for declaring multiple variables of the same type in a single line, similar to Go. However, the syntax is slightly different, using commas to separate the variables and their initializations.

Type inference in Java is more limited compared to Go. It’s only available for local variables (not class fields) and requires initialization at the point of declaration.

Remember that in Java, all code must be inside a class, and the entry point of the program is the main method of a public class.