Tag: java

Quizzes (35) Questions (265)

Questions Related to java

Multiple choice java

Assume the following method is properly synchronized and called from a thread A on an object B: wait(2000); After calling this method, when will the thread A become a candidate to get another turn at the CPU?

After object B is notified, or after two seconds
After the lock on B is released, or after two seconds
Two seconds after object B is notified
Two seconds after lock B is released.

Reveal answer Fill a bubble to check yourself

Multiple choice java

for(Object obj: expression) { } What interface must the ?expression? implement in order for you to use it with enhanced for loop construct?

Iterator
Map
Enumeration
Iterable

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Multiple choice java

Given:

TreeSet map = new TreeSet();
 map.add("one");
 map.add("two");
 map.add("three");
 map.add("four"};
 map.add("one");
 Iterator it = map.iterator();
 while (it.hasNext() ) {
 System.out.print( it.next() + " " );
 }

Compilation fails
one two three four
four three two one
four one three two
one two three four one
one four three two one

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Multiple choice java

Which is true about a method-local inner class?

It must be marked final
It can be marked abstract
It can be marked public
It can be marked static

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Multiple choice java

Which is true about an anonymous inner class?

It can extend exactly one class and implement exactly one interface
It can extend exactly one class and can implement multiple interfaces
It can extend exactly one class or implement exactly one interface
It can implement multiple interfaces regardless of whether it also extends a class
It can implement multiple interfaces if it does not extend a class

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Multiple choice java

Which is true?

The java command can access classes from more than one package, from a single JAR file.
JAR files can be used with the java command but not with the javac command.
In order for JAR files to be used by java, they MUST be placed in the /jre/lib/ext sub-directory within the J2SE directory tree.
When a part of a directory tree that includes subdirectories with files is put into a JAR file, all of the files are saved in the JAR file, but the subdirectory structure is lost.

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Multiple choice java

Which of the following statement is true?

X extends Y is correct if and only if X is a class and Y is an interface
X extends Y is correct if and only if X is an interface and Y is a class
X extends Y is correct if X and Y are either both classes or both interfaces
X extends Y is correct for all combinations of X and Y being classes and/or interfaces.

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Multiple choice java

Select a statement that best indicate a situation with low coupling.

The attributes of the class are all private
The class refers to a small number of other objects
The object contains only a small number of variables
The object is referred to using an anonymous variable, not directly
The reference variable is declared for an interface type, not a class. The interface provides a small number of methods

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Multiple choice java

Applications in a J2EE architecture

must be created via a Java IDE.
can run on different machines, but only with the same Operating System.
are typically based on Servlets, JSPs and Enterprise Java Beans.
need no runtime environment.

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Multiple choice java

The EJB specification architecture does NOT define

transactional components.
client side security and encryption.
distributed object components.
server-side components.

Reveal answer Fill a bubble to check yourself

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