JavaScript: Closures and Statements Trivia Quiz

1. The Groovy do statement is identical to Java's do statement.

True

False

Groovy does not have a do statement (I don't know why).

Explanation

Groovy does not have a do statement (I don't know why).

2. When you return from a closure which is called by an iterative method, you stop the iteration process.

True

False

The iteration process continues on the remaining elements of the object that you are iterating over.

Explanation

The iteration process continues on the remaining elements of the object that you are iterating over.

3. Groovy truth is identical to Java truth.

True

False

There are subtle and important differences in truthiness between the two languages.

Explanation

There are subtle and important differences in truthiness between the two languages.

4. The Groovy for/in loop has the same syntax as Java's for/each loop.

True

False

for (x in collection) {} // Groovy
for (x: collection) {} // Java

Explanation

for (x in collection) {} // Groovy
for (x: collection) {} // Java

5. In Java the order of case branches within a switch statement is immaterial.

True

False

This is true because Java is very restrictive on the types that you can switch on.

Explanation

This is true because Java is very restrictive on the types that you can switch on.

6. Groovy does not have a way to test for reference equality.

True

False

You test for reference equality by calling the is() method.

Explanation

You test for reference equality by calling the is() method.

7. Unlike a method a closure can only take one parameter.

True

False

A closure is very much like a method and can take any number of parameters.

Explanation

A closure is very much like a method and can take any number of parameters.

8. What does this code do? List numbers = [1,2,3,4] println numbers.collect{it * 2}

Prints a list of the first four even numbers

Prints four even numbers each on its own line

Prints the variable numbers itself

The collect() method returns a list of four even numbers to the println() method.

Explanation

The collect() method returns a list of four even numbers to the println() method.

9. Consider this Groovy method and its invocation: def foo() { def m = [:] m.a = 0 m.b = 1 } def val = foo() The variable val:

Is of type Map

Is undefined since foo has no return value

Is of type Integer since the last statement of foo is of type Integer

Here the return statement is implicitly the last statement.

Explanation

Here the return statement is implicitly the last statement.

10. (Fill in the blank) The _____ operator invokes the compareTo method of a class that implements the Comparable interface.

The spaceship operator is used to invoke the compareTo method of a class that implements the Comparable interface. This operator is typically used to compare two objects and determine their relative order.

Explanation

The spaceship operator is used to invoke the compareTo method of a class that implements the Comparable interface. This operator is typically used to compare two objects and determine their relative order.

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11. In JavaScript, the keyword _______ is used to declare a variable with block-level scope.

In JavaScript, let is used to declare variables with block-level scope. This means the variable is only accessible within the code block (defined by curly braces {}) where it is declared. This allows for better control over variable visibility and helps prevent accidental modification or conflicts in larger programs.

Explanation

In JavaScript, let is used to declare variables with block-level scope. This means the variable is only accessible within the code block (defined by curly braces {}) where it is declared. This allows for better control over variable visibility and helps prevent accidental modification or conflicts in larger programs.

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JavaScript: Closures And Statements Trivia Quiz