Java Exam Review 100% Accurate!!
What is Java EE? - ANSWERJava Enterprise Edition. For making large-scale shit like Distributed and
networking systems or Enterprise web-based applications.
What is Java ME? - ANSWERJava Micro Edition. Subset of the SE or standard edition. Used for
recourse starved devices like appliances or security cameras.
What is the JDK? - ANSWERJava Development Kit. Used to develop and run java applications.
Includes JRE, java to interpret, javac to compile.
What is the JRE? - ANSWERJava Runtime Environment. Used if you simply just want to run java
applications.
What is the JVM? - ANSWERJava Virtual Machine. Park of the JDK. Used to execute bytecodes.
What are bytecodes? - ANSWERJava instructions set. Platform specific. Executed on any platform
with the JVM installed. Enables "Write once run anywhere".
What is JIT? - ANSWERJust-in-time compiler. Used by JVM to convert bytecodes into machine
language. Faster. Example is Oracle Java HotSpot compiler.
What are the 5 phases of Java development? - ANSWEREdit in VIM
Compile to bytecodes
Load into JVM
Verify to ensure security
Execute to run
What is the difference between a ".java" file and a ".class" file? - ANSWER".java" is your source code
file that you edit. The ".class" file is the one that the compiler creates that contains the compiled
program in bytecode format.
, What is Javadoc and what is it used for? - ANSWERIgnored by compiler. The javadoc utility program
uses it to prepare your documentation in HTML format.
How can you tell if two classes are in the same package? - ANSWERIf they are stored in the same
directory.
What are three exceptions to the rule that all packages must be imported? - ANSWERDefault
package, Fully qualified names, and the classes in Java.lang.
How can you tell how many command line arguments are passed to a command line? If no
arguments are passed, how can you tell that? - ANSWERBy checking the String array's length
attribute.
What are the parts that make up the main function declaration? - ANSWERpublic static void
main(String[] args)
What is each part of the main function declaration doing? - ANSWERStatic tells the JVM that it does
not need to create an object of the class in which main is declared. Void says that the function is not
going to return a value.
Do variables need to be declared in Java? - ANSWERYes
What is the difference between a primitive type and a reference type? - ANSWERPrimitive types are
like int, double, bool. Reference are classes or pointers to values within a class. Reference are
initialized to null. String is a reference type.
What are the 8 primitive data types? - ANSWERboolean
byte
char
short
int
long
float
double
What is Java EE? - ANSWERJava Enterprise Edition. For making large-scale shit like Distributed and
networking systems or Enterprise web-based applications.
What is Java ME? - ANSWERJava Micro Edition. Subset of the SE or standard edition. Used for
recourse starved devices like appliances or security cameras.
What is the JDK? - ANSWERJava Development Kit. Used to develop and run java applications.
Includes JRE, java to interpret, javac to compile.
What is the JRE? - ANSWERJava Runtime Environment. Used if you simply just want to run java
applications.
What is the JVM? - ANSWERJava Virtual Machine. Park of the JDK. Used to execute bytecodes.
What are bytecodes? - ANSWERJava instructions set. Platform specific. Executed on any platform
with the JVM installed. Enables "Write once run anywhere".
What is JIT? - ANSWERJust-in-time compiler. Used by JVM to convert bytecodes into machine
language. Faster. Example is Oracle Java HotSpot compiler.
What are the 5 phases of Java development? - ANSWEREdit in VIM
Compile to bytecodes
Load into JVM
Verify to ensure security
Execute to run
What is the difference between a ".java" file and a ".class" file? - ANSWER".java" is your source code
file that you edit. The ".class" file is the one that the compiler creates that contains the compiled
program in bytecode format.
, What is Javadoc and what is it used for? - ANSWERIgnored by compiler. The javadoc utility program
uses it to prepare your documentation in HTML format.
How can you tell if two classes are in the same package? - ANSWERIf they are stored in the same
directory.
What are three exceptions to the rule that all packages must be imported? - ANSWERDefault
package, Fully qualified names, and the classes in Java.lang.
How can you tell how many command line arguments are passed to a command line? If no
arguments are passed, how can you tell that? - ANSWERBy checking the String array's length
attribute.
What are the parts that make up the main function declaration? - ANSWERpublic static void
main(String[] args)
What is each part of the main function declaration doing? - ANSWERStatic tells the JVM that it does
not need to create an object of the class in which main is declared. Void says that the function is not
going to return a value.
Do variables need to be declared in Java? - ANSWERYes
What is the difference between a primitive type and a reference type? - ANSWERPrimitive types are
like int, double, bool. Reference are classes or pointers to values within a class. Reference are
initialized to null. String is a reference type.
What are the 8 primitive data types? - ANSWERboolean
byte
char
short
int
long
float
double
