1Z0-811 Multiple Select — 30 Questions

Question 1

Which TWO of the following are legal ways to declare and initialize an array?

Accepted Answer

int[] arr = new int[]{1,2,3};. It uses the valid syntax `int[] arr = new int[]{1,2,3};` which declares an array variable of type `int[]`, creates a new array object with an initializer list, and assigns it to the variable. This is a legal way to both declare and initialize an array in a single statement, as the array size is inferred from the number of elements in the initializer.

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int arr = {1,2,3};

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int arr[];

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int[3] arr;

Question 2

Which THREE statements are true about the Java logging API (java.util.logging)?

Accepted Answer

Handlers can be attached to loggers to output messages. The Java Logging API allows Handlers (such as ConsoleHandler, FileHandler, or custom handlers) to be attached to Logger objects to output log messages to destinations like the console, files, or network sockets. This is a core design pattern of the API: loggers produce log records, and handlers are responsible for publishing them.

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The default configuration logs all messages at FINEST level

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All loggers automatically forward messages to the root logger

Question 3

Which TWO are valid Java identifiers? (Choose two.)

Accepted Answer

$test. ($test) is a valid Java identifier because identifiers can begin with a dollar sign ($) or an underscore (_), followed by any combination of letters, digits, dollar signs, or underscores. The Java Language Specification (JLS §3.8) explicitly allows the dollar sign as a starting character, though it is conventionally reserved for mechanically generated names.

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class

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my-var

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2ndVar

Question 4

Which TWO statements about constructors are true? (Choose two.)

Accepted Answer

Constructors have no return type. Constructors in Java do not have a return type, not even void. If a return type is specified, the Java compiler treats the method as a regular method, not a constructor. This is a fundamental syntactic rule defined in the Java Language Specification (JLS §8.8).

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The compiler always provides a default constructor

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Constructors can be declared as abstract

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Constructors have a return type of void

Question 5

Which three statements about arrays are correct? (Choose three.)

Accepted Answer

Arrays are objects in Java.. In Java, arrays are objects that are dynamically created and can be assigned to variables of type Object, cloned via the clone() method, and have a length field (not a method). They inherit from java.lang.Object and are treated as reference types, even when they store primitive values.

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The size of an array can change after creation.

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The length of an array must be specified at compile time with a constant expression.

Question 6

Which three of the following are valid ways to declare and initialize a variable of type int? (Choose three.)

Accepted Answer

int b = 0xA;. `0xA` is a hexadecimal integer literal in Java, representing the decimal value 10. Java allows hexadecimal literals using the prefix `0x` or `0X`, and they are valid for initializing an `int` variable.

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int e = 10.0;

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int c = 0b2;

Question 7

Which two statements about the Arrays class are true? (Choose two.)

Accepted Answer

The Arrays class provides a method to fill an array with a specific value.. The `Arrays.fill()` method allows you to assign a specific value to every element of an array, or to a specified range within the array. This is a static utility method provided by the `java.util.Arrays` class, and it works for both primitive and object arrays.

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The Arrays class provides a method to sort only arrays of primitive types.

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The Arrays class provides a method to perform binary search on any array.

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The Arrays class provides a method to deep copy an array.

Question 8

Which two expressions evaluate to true? (Choose two)

Accepted Answer

10 > 5. The expression `10 > 5` uses the greater-than operator, which evaluates to `true` since 10 is indeed greater than 5. Option D is correct because `!false` evaluates to `true`, and the logical OR operator (`||`) returns `true` if at least one operand is `true`, so `false || true` yields `true`.

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true && false

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'a' == 'b'

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3 < 3

Question 9

Which THREE statements are true about passing arrays to methods in Java?

Accepted Answer

Varargs parameters allow passing zero or more arguments of the specified type.. Varargs (variable-length arguments) in Java allow a method to accept zero or more arguments of a specified type, using the syntax `Type... param`. This is syntactic sugar for an array parameter, and the method body treats it as an array. This enables flexible method invocation without requiring the caller to explicitly create an array.

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If the method modifies elements of the array, the caller does not see the changes.

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If the method assigns a new array to the parameter, the caller's variable is updated.

Question 10

Which THREE are valid ways to declare and initialize an integer variable in Java? (Choose three.)

Accepted Answer

int x = 1_000;. Java allows underscores in numeric literals (introduced in Java 7) to improve readability, and `1_000` is a valid integer literal representing 1000. The compiler simply ignores the underscores during parsing.

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int x = 2.0;

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int x = 0xG;

Question 11

Which two statements about the break statement in Java are true?

Accepted Answer

break can be used inside a switch case. The break statement is used inside a switch case to terminate the switch block and prevent fall-through to subsequent cases. Without break, execution would continue into the next case, which is often unintended.

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break can be used without any enclosing loop

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break is used to skip to next iteration

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break exits the current loop iteration

Question 12

Which TWO of the following are valid benefits of using inheritance in Java? (Choose two.)

Accepted Answer

Allows polymorphic behavior. Options B and C are correct. Inheritance promotes code reuse by allowing subclasses to reuse fields and methods from superclasses, reducing redundancy. It also enables polymorphic behavior through method overriding, allowing objects to be treated as instances of their parent class. Option A is incorrect because inheritance actually increases coupling between classes, which is generally considered a disadvantage, not a benefit. Option D is incorrect because encapsulation is enforced through access modifiers (private, protected, public), not inheritance. Option E is incorrect because inheritance can actually complicate debugging by introducing dependencies across classes.

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Increases coupling between classes

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Enforces encapsulation

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Simplifies debugging

Question 13

Which THREE of the following are primitive data types in Java?

Accepted Answer

boolean. (boolean) is correct because boolean is one of the eight primitive data types in Java, representing a single bit of information with only two possible values: true or false. It is not an object and does not have methods, unlike reference types such as Boolean (the wrapper class).

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void

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String

Question 14

Which three statements about String immutability are true? (Choose three)

Accepted Answer

The intern() method returns a String from the pool. The `intern()` method returns a canonical representation of the string from the string pool, ensuring that strings with the same content share the same memory reference, which is a key aspect of immutability and memory optimization in Java.

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String objects can be modified after creation

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String objects can be changed by calling methods

Question 15

Which TWO methods correctly modify the passed array in place?

Accepted Answer

public void zeroOut(int[] a) { for (int i = 0; i < a.length; i++) a[i] = 0; }. It directly modifies each element of the passed array by assigning 0 to a[i] within the loop. In Java, when an array is passed to a method, the method receives a reference to the same array object, so changes to the array's elements are reflected in the caller's array.

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public void reset(int[] a) { a = new int[10]; }

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public void swap(int[] a) { int[] temp = a; a = new int[1]; a[0] = temp[0]; }

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public void setFirst(int[][] a) { a = new int[1][1]; a[0][0] = 5; }

Question 16

Which THREE of the following are primitive data types in Java?

Accepted Answer

double. `double` is one of the eight primitive data types in Java, used to store floating-point numbers with double precision (64-bit IEEE 754). It is a fundamental type that holds a numeric value directly, not an object reference.

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String

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array

Question 17

Which two of the following are primitives in Java? (Choose two.)

Accepted Answer

byte. A is correct because `byte` is a primitive data type in Java that stores 8-bit signed integers, ranging from -128 to 127. It is one of the eight primitive types defined in the Java language specification, not an object or reference type.

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String

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Integer

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Boolean

Question 18

Which THREE are primitive data types in Java? (Choose three.)

Accepted Answer

double. `double` is one of the eight primitive data types in Java, used to represent double-precision 64-bit IEEE 754 floating-point numbers. Primitives are predefined by the language and stored directly in stack memory, not as objects.

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Integer

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String

Question 19

Which TWO access modifiers allow access from a subclass in a different package?

Accepted Answer

protected. (protected) is correct because the protected access modifier allows access to members of a superclass by subclasses in different packages, provided the subclass inherits from the superclass. Option E (public) is also correct because public members are accessible from any class, regardless of package or inheritance.

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private

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static

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default (no modifier)

Question 20

Which TWO of the following are primitive data types in Java?

Accepted Answer

double. (double) is correct because double is a 64-bit IEEE 754 floating-point primitive data type in Java, used for decimal values with double precision. Option D (int) is correct because int is a 32-bit signed two's complement integer primitive, the default integer type in Java. Both are part of the eight primitive types defined in the Java Language Specification.

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String

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Integer

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Boolean