Java 1
Identifier may not have:
(1) first character may not be a digit,$,or special character (2) no spaces
Identifier may have:
(1) letters a-z || A-Z (2) digits 0-9 (3) underscores (_) (4) dollar sign ($) (5) Case Sensitive
Examples of double data types:
29.75, 1.76, and 31.51 are double data types.
What does this number look like with scientific notation? 47,281.97 ==
4.728197 x 104. (However Java uses E notation)
How many bits are in a Byte?
8
A value that is written into the code of a program.
A literal
The JVM is a program that emulates what?
A micro-processor
Characteristic of a final identifier
All caps, constant, never changes
What Java often referred to as?
An interpreted language
How are escape sequences treated by the compiler?
As 1 character instead of multiple
Java uses what notation to represent values in scientific notation.
E notation (4.728197X104 == 4.728197E4.)
% means
Modulus - binary - Ex: remainder = value % 5;
* means
Multiplication- binary Ex: tax = cost * rate;
Can Byte code instructions be directly executed directly by the CPU?
No
What numbers can integer data types not hold?
Numbers that have a decimal point in them (0.2)
Describe the Java Program Development Process.
Picture Here!
Data types built into the Java Language and are not derived from classes
Primitive
What is a micro-processor?
Processor a multipurpose, clock driven, register based, digital-integrated circuit which accepts binary data as input, processes it according to instructions stored in its memory, and provides results as output.
Who determines the number and type of variables a program will need.
Programmers
Give an example of a variable bring assigned a String literal:
String value = "Hello"; (String Objects unlike other objects can be created this way)
Give an example of variable being created using the "new" keyword
String value = new String("Hello"); (All objects must used this to be created)
What will be discovered in the program during compilation?
Syntax Errors (When will they be found?)
Mistakes that the programmer has made that violates the rules of the programming language.
Syntax Errors(Definition)
What is used to edit and save a Java source code file?
Text editor
If a .java file has a public class, the class must have what?
The same name as the file.
(T/F) Comments are ignored by the compiler.(Why)
True
(T/F) For every left brace, or opening brace, there must be a corresponding right brace, or closing brace.(Why)
True
(T/F) Floating-point literals can be represented in scientific notation.
True 47,281.97 == 4.728197 x 104.
Who writes java programming statements?
Who is the Java Programmer?
How are statements terminated?
With semicolons
Is Java a case-sensitive language?
Yes
Java Reserved Keywords - a
abstract, assert,
+ (means)
addition - binary - Ex: total = cost + tax:
\\
backslash- causes a backslash to be printed
\b
backspace - move cursor left by one position
Java Reserved Keywords - f
false, for, final, finally, float
Run using java or javac
java file name interpreter
Compile using java or javac
javac - filename.java
Special meaning in a programming language are called
keywords
Java Reserved Keywords - r
return
Java Reserved Keywords - s
short, static, strictfp, super, switch, synchronized
\'
single quote - causes a single quotation mark to be printed
- (means)
subtraction -binary - Ex: cost = total - tax;
\t
tab
Name a method of the String class
the length method (stringSize = value.length();
Java Reserved Keywords - t
this, throw, transient, true, try
A named storage location in the computer's memory
variable
Java Reserved Keywords - v
void, volatile
Java Reserved Keywords - w
while
Name Java's 5 arithmetic operators:
+, -, *, /, %
Byte code files end with what?
.class file extension.
Is this correct? grossPay = 1257.00;
// Correct.
Is this correct? grossPay = $1,257.00;
// ERROR! (Literals not allowed to have currency symbols or commas)
4 % 2 =
0
3 % 2=
1
How does the JVM execute instructions?
As they are read.
Name all 8 Jave Primitive data types with values
Boolean(1 bits), byte(8 bits), char(16 bits), short(16 bits), int(32 bits), float(32 bits), long(64 bits), double(64 bits)
Java Reserved Keywords - b
Boolean, break, byte
The machine language of the Java Virtual Machine (JVM) and cannot be directly executed directly by the CPU.
Byte code instructions (Definition)
What are not considered statements?
Comments, class headers, method headers, and braces
This is run using a source code file as input.
Compiler (How does it run?)
A program that translates source code into an executable form:
Compiler (What is it?)
What creates another file that holds the translated instructions?
Compiler(What does it create?)
/ means
Division- binary - Ex: salePrice = original / 2;
___BLANK___also called double precision (15 decimal points) floating-point numbers.
Double
Literals cannot contain what?
Embedded currency symbols or commas.
What do most compilers translate source code into?
Executable files containing Machine code
(T/F) Identifiers may be any of the Java reserved keywords.(Why)
False
(T/F) Java applications don't need to have a main method.(Why)
False
___BLANK_____ also called single precision (7 decimal points) floating-point numbers.
Float
In Java there are two data types that can represent floating-point numbers. What are they?
Float and double
Integers embedded in java source code are called?
Integer literals
What is another name for JVM?
Interpreter
What language is a strongly-typed language.
Java
Java programming statements are?
Source code
What has a .java file extension?
Source code files
The Java compiler translates a Java source file into a file that contains what type of instructions
byte code instructions
Name all the integer data types
byte, short, int, long
\r
carriage return - cursor goes to the beginning of the current line, not the next line
Java Reserved Keywords - c
case, catch, char, class, const
Identifiers are programmer-defined names for:
classes, variables, methods
Java Reserved Keywords - d
default, do, double
The default type for floating point literals is:
double
\\"
double quote - causes a double quotation mark to be printed
Java Reserved Keywords - e
else, enum, extends
When floating point numbers are embedded into Java source code they are called?
floating point literals.
Data types that allow fractional values are called?
floating-point numbers
1.7 and -45.316 are examples of what type of numbers?
floating-point numbers.
Java Reserved Keywords - g
goto
Java Reserved Keywords - i
if, implements, import, instanceof, int, interface
How must all Java programs be stored ?
in a file with a .java file extension.
Java Reserved Keywords - L
long
Example of Data type conversion
long i = short short i = long (X) - not allowed
Java Reserved Keywords - n
native, new, null
\n
newline
A .java file may contain many classes but may only have how many public classes?
one public class.
Java Reserved Keywords - p
package, private, protected, public
