D286 Java Fundamentals - Set 1 - Part 1

Correct Answer: public static void main(String[] args)

The Java Virtual Machine begins execution at public static void main(String[] args). It must be public, static, and return void to be recognized as the entry point.

Correct Answer: Java Virtual Machine

The Java Virtual Machine executes compiled Java bytecode, providing platform independence by translating bytecode into instructions for the host system.

Correct Answer: .class

The Java compiler translates .java source files into .class files containing bytecode, which the JVM then executes.

Correct Answer: int

int is one of Java's eight primitive types. String, ArrayList, and Integer are reference types (objects), with Integer being the wrapper class for int.

Correct Answer: 32

A Java int is a 32-bit signed two's complement integer, holding values from -2,147,483,648 to 2,147,483,647.

Correct Answer: BigDecimal is preferred over primitives for exact decimal values

Floating-point types like double introduce rounding errors, so BigDecimal is preferred for exact decimal arithmetic such as monetary calculations.

Correct Answer: 0

Instance fields receive default values automatically: numeric types default to 0, boolean to false, and reference types to null.

Correct Answer: false

A boolean instance field defaults to false when not explicitly initialized.

Correct Answer: final

The final keyword prevents reassignment of a variable after initialization. Java reserves const but does not use it.

Correct Answer: The field belongs to the class rather than to any instance

A static field is shared by all instances of the class and belongs to the class itself, accessible without creating an object.

Correct Answer: private

The private modifier restricts access to within the declaring class, forming the basis of encapsulation.

Correct Answer: public

The public modifier allows access from any class in any package.

Correct Answer: Accessible within the same package only

With no modifier, a member has package-private (default) access, visible only to classes in the same package.

Correct Answer: Access within the package and by subclasses in other packages

Protected members are accessible within the same package and by subclasses, even when those subclasses reside in a different package.

Correct Answer: // comment text

Java uses // for single-line comments and /* ... */ for multi-line comments. Javadoc comments begin with /**.

Correct Answer: +

The + operator concatenates Strings in Java. When either operand is a String, the other is converted to its String representation.

Correct Answer: 3

Integer division discards the fractional part, so 7 / 2 evaluates to 3. To get 3.5, at least one operand must be a floating-point type.

Correct Answer: 1

The modulus operator returns the remainder of division. 7 divided by 2 leaves a remainder of 1.

Correct Answer: Returns the current value, then increments i

Post-increment (i++) yields the original value of i in the expression and then increases i by one. Pre-increment (++i) increments first, then yields the new value.

Correct Answer: ==

The == operator compares primitive values for equality. A single = performs assignment, and equals() compares object content.