1z0-819 Java SE 11 Developer Questions and Answers

Java prioritizes garbage collection.

Java has a library of built-in functions that can be used to enable pipeline burst execution.

Java monitors and optimizes code that is frequently executed.

Java automatically parallelizes code execution.

The output will be exactly 2 1 3 4 5.

The program prints 1 4 2 3, but the order is unpredictable.

Replacing forEach() with forEachOrdered(), the program prints 2 1 3 4 5, but the order is unpredictable.

Replacing forEach() with forEachOrdered(), the program prints 1 2 3 4 5.

Replacing forEach() with forEachOrdered(), the program prints 2 1 3 4 5.

null

nothing

It fails to compile.

java.lang.IllegalAccessException is thrown.

Student

An exception is thrown at runtime.

42=(x+y)=42

42=(x+y)=6

6=(x+y)=42

6=(x+y)=6

2134

2143

214

234

Runnable r = “Message” −> System.out.println();

Runnable r = () −> System.out::print;

Runnable r = () -> {System.out.println(“Message”);};

Runnable r = −> System.out.println(“Message”);

Runnable r = {System.out.println(“Message”)};

An exception is thrown at runtime.

Hello WorldHello World

Hello World Hello World

Hello WorldHelloWorld

HelloHello WorldHelloWorld

You accept the change because -noverify is necessary for your code to run with the latest version of Java.

You reject the change because -Xms8g -Xmx8g uses too much system memory.

You accept the change because -noverify is a standard option that has been supported since Java 1.0.

You reject the change because -noverify is a critical security risk.

Create a method that validates the hostName and portNumber parameters before opening the socket.

Make enableService private.

Enclose the call to new Socket In an AccessController.doPrivileged block.

i—;

continue b;

break b;

j--;

continue a;

break a ;

jmod describe

java Hello.java

jdeps --list-deps

jar --show-module-resolution

java --show-module-resolution

The compilation fails.

abdf

abd

adf

abcd

MessageBundle_en_US.properties

MessageBundle_en.properties

MessageBundle_fr_FR.properties

MessageBundle_US.properties

MessageBundle.properties

The code compiles but does not print any result.

The code prints 25.

The code does not compile.

The code throws an exception at runtime.

9001: java.io.FileNotFoundException: MyFile.txt-MyFile.txt

9001: APPLICATION ERROR-9001-MyFile.txt

9001: java.io.FileNotFoundException: MyFile.txt-MyFile.txt

9001: APPLICATION ERROR-9001-MyFile.txt

Compilations fails at Line 1.

An instance variable can be declared with the static modifier.

A local variable can be declared with the final modifier.

An abstract method can be declared with the private modifier.

An inner class cannot be declared with the public modifier.

An interface can be declared with the protected modifier.

Option A

Option B

Option C

Option D

float z = (float)(Math.round((float)x/y*100)/100);

float z = Math.round((int)(x/y),2);

float z = Math.round((float)x/y,2);

float z = Math.round((float)x/y*100)/(float)100;

MyInterface1

MyInterface3

MyInterface5

MyInterface2

MyInterface4

Fox class does not have to override inhabit method, so long as it does not try to call it.

Fox class does not have to override the inhabit method if Forest and Town provide compatible implementations.

Fox class must implement either Forest or Town interfaces, but not both.

The inhabit method implementation from the first interface that Fox implements will take precedence.

Fox class must provide implementation for the inhabit method.

Keys: 4 Values: 4 Map: 0

Keys: 4 Values: 4 Map: 4

The compilation fails.

Keys: 0 Values: 0 Map:

Keys: 0 Values: 0 Map: 0

A ClassCastException is thrown at runtime.

AnotherClass#methodA()AnotherClass#methodA()

The compilation fails.

SomeClass#methodA()AnotherClass#methodA()

AnotherClass#methodA()SomeClass#methodA()

SomeClass#methodA()SomeClass#methodA()

java, jdeps

javac, jlink

jar, jlink

javac, jar

A compilation error is thrown.

Message from Copier: Attempt00

Message from Abstract Copier: Attempt00

A runtime error is thrown.

The compilation fails because there is no zero args constructor defined in class X.

The compilation fails because either class X or class Y needs to implement the toString() method.

The compilation fails because a final class cannot extend another class.

The compilation succeeds.

-1 : 2

2 : -1

2 : 3

3 : 0

privilege escalation attack against the OS running the customer code

SQL injection attack against the specified host and port

XML injection attack against any mlib server

none because the customer code base must also be granted SocketPermission

denial of service attack against any reachable machine

After Line 4, add indexReader.close().

On Line 3, enclose processData(dataReader) with try with resources.

After Line 3, add dataReader.close().

On Line 1, use try with resources when opening each dataReader.

Before Line 1, check the size of dataFiles to make sure it does not exceed a threshold.

line n1

line n3

line n2

line n4

System.out is the standard output stream. The stream is open only when System.out is called.

System.in cannot reassign the other stream.

System.out is an instance of java.io.OutputStream by default.

System.in is the standard input stream. The stream is already open.

setAllCounts

setACount

setGCount

setCCount

setTCount

A NullPointerException is thrown at run time.

The compilation fails.

1

Null

null

1

1

1

A ClassCastException is thrown at run time.

Interfaces cannot have protected methods but abstract classes can.

Both interfaces and abstract classes can have final methods.

Interfaces cannot have instance fields but abstract classes can.

Interfaces cannot have static methods but abstract classes can.

Interfaces cannot have methods with bodies but abstract classes can.

public Collection foo(Collection arg) { ... } overrides Foo.foo.

public Collection foo(Stream arg) { ... } overloads Foo.foo.

public List foo(Collection arg) { ... } overrides Foo.foo.

public Collection foo(Collection arg) { ... } overloads Foo.foo.

public Collection bar(Collection arg) { ... } overloads Foo.foo.

public Iterable foo(Collection arg) { ... } overrides Foo.foo.

public void x() { }

public void z() { }

public void x() { }

protected void y() { super.y(); }

public void z() { }

void x() { }

public void y() { }

public void z() { }

void x() { super.y(); }

public void z() { }

void x() { }

public void z() { }