The document provides an overview of key concepts in the Java programming language including: 1. Java language fundamentals including building blocks like identifiers, literals, variables, and wrapper classes. Different types of literals like integral, floating point, character, string and boolean are described. 2. Control structures in Java including selection statements like if-else and switch statements, and iterative statements like while, do-while and for loops. Jump statements like break, continue and return are also covered. 3. Other concepts discussed include arrays, declaring and initializing array variables, and creating arrays using the new operator in Java.

1. Programming in JAVA
Unit-II
BY
N.RUBA
ASST.PROF/DEPT. OF CA,
BON SECOURS COLLEGE FOR WOMEN,
THANJAVUR.
1

2. UNIT-II Chapter 3
Java language fundamentals
 Building blocks of Java
 Java as a programming language, follows a set of rules
 Predfefined conventions that specify how syntactically legal
constructs can be formed using the language elements.
 A semantic definition specifies the meaning of syntactically
legal constructs.
2

3. LEXICAL TOKENS
low level language elements are known as
lexical elements.
3
OPERATORS
SEPARATORS
LITERALS
WHITE SPACE
IDENTIFIER
KEY WORD
JAVA TOKENS

4. Identifiers
 Identifiers are the names of variables, methods, classes,
packages and interfaces. Unlike literals they are not the
things themselves, just ways of referring to them. In the
HelloWorld
program, HelloWorld, String, args, main and println are
identifiers.
 Identifiers must be composed of letters, numbers, the
underscore _ and the dollar sign $. Identifiers may only
begin with a letter, the underscore or a dollar sign.

4

5. literals
 Literals in Java – Integral, Floating-Point, Char, String,
Boolean
 Literals are number, text, or anything that represent a
value. In other words, Literals in Java are the constant
values assigned to the variable. It is also called a constant.
 For example,
 int x = 100;
5

6. Literals
integral
Floating point
Char
string
boolean
6

7. 1. Integral literal
 Hexa-Decimal (Base 16)
 Digits 0-9 are allowed and also characters from a-f are
allowed in this form. Furthermore, both uppercase and
lowercase characters can be used, Java provides an
exception here.e.g A34,76F
 Decimal-(base 10)0-9e.g 598
 Octal (base -8)0-7 e.g 675
7

8. 2.Floating-Point Literals in Java
 Here, datatypes can only be specified in decimal forms
and not in octal or hexadecimal form.
 Decimal (Base 10)
 E.g 5.78
8

9. 3.
Char Literals in Java
These are the four types of char-
 Single Quote
Java Literal can be specified to a char data type as a single character within a single quote.
char ch = 'a';
 Char as Integral
A char literal in Java can specify as integral literal which also represents the Unicode value of a character.
Furthermore, an integer can specify in decimal, octal and even hexadecimal type, but the range is 0-65535.
char ch = 062;
 Unicode Representation
Char literals can specify in Unicode representation ‘uxxxx’. Here XXXX represents 4 hexadecimal numbers.
char ch = 'u0061';// Here /u0061 represent a.
 Escape Sequence
Escape sequences can also specify as char literal. E.g-char ch = 'n';
9

10.  4. String Literals
 Java String literals are any sequence of characters with a
double quote.
 String s = "Hello";
 5. Boolean Literals
 They allow only two values i.e. true and false.
 boolean b = true;
10

11. Variable declaration in Java
 Variable in Java is a data container that stores the data
values during Java program execution. Every variable is
assigned data type which designates the type and quantity
of value it can hold.
 Variable is a memory location name of the data. The Java
variables have mainly three types :
 Local,
 Instance and
 Static.
 variable in a program can perform 2 steps
 Variable Declaration
 Variable Initialization
11

12. Variable Declaration:
 To declare a variable, must specify the data type & give the
variable a unique name.
 Examples of other Valid Declarations are
int a,b,c;
float pi;
double d;
char a;
12

13. Variable initialization
 To initialize a variable, you must assign it a valid value.
 Example of other Valid Initializations are
pi =3.14f;
do =20.22d;
a=’v’;
You can combine variable declaration and initialization.
 Example :
int a=2,b=4,c=6;
float pi=3.14f;
double do=20.22d;
char a=’v’;
13

14. Types of variables
In Java, there are three types of variables:
 Local Variables
 Instance Variables
 Static Variables
1) Local Variables
Local Variables are a variable that are declared inside the
body of a method.
2) Instance Variables
Instance variables are defined without the STATIC keyword
.They are defined Outside a method declaration. They are
Object specific and are known as instance variables.
3) Static Variables
Static variables are initialized only once, at the start of the
program execution. These variables should be initialized
first, before the initialization of any instance variables.
Example: Types of Variables in Java
class sum
{
static int a = 1; //static variable
int data = 99; //instance variable
void method()
{
int b = 90; //local variable
}
}
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15. Wrapper classes in Java
 Each primitive data type in java has a corresponding
wrapper class.
 The wrapper class in Java used to represent a primitive
data type as an object. It is used to convert primitive into
object and object into primitive.
 Wrapper class belong to the java.lang.package
 Wrapper classes for integers and floating-point numbers
are sub-classes of the number class in the java.lang
package.
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16. Wrapper classes for primitive
datatype
Primitive data type Wrapper classes
int Integer
byte Byte
short Short
long Long
float Float
double Double
16

17. Operators in Java
An operator takes one or more arguments and produces new value.
 Operator in Java is a symbol which is used to perform operations. For example: +, -, *, / etc.
Types of operators in Java which are given below:
 Unary Operator,
 Arithmetic Operator,(or)mathematical
 Shift Operator,
 Relational Operator,
 Bitwise Operator,
 Logical Operator,
 Ternary if-else Operator
 Comma operator
 Assignment Operator
 String operator +
 Operator precedence
 Casting operators
17

18.  Ternary if-else operator
 Boolean-exp?value():value1
 Comma operator
 Used in for loops
 E.g for (i=1,j=10;i<10;i++,j--)
 String operator +
 used to concatenate two strings
 Casting operator
 Used to make type conversions
18

19. Control structures
Control
structures
Selection statements
Iterative statements
Jump statements
19

20. Selection or branching
 if statement to test a
condition and decide the
execution of a block of
statements based on that
condition result. The if
statement checks, the given
condition then decides the
execution of a block of
statements. If the condition is
True, then the block of
statements is executed and if
it is False, then the block of
statements is ignored.
20

21. If-else
21

22. Nested if statement in java
 Writing an if statement inside another if-statement is called
nested if statement.
Syntax
if(condition_1){
if(condition_2){
inner if-block of statements;
...
}
...
}
22

23. if-else if statement in java
 Writing an if-statement inside else of an if statement is called if-else-if statement.
Syntax
if(condition_1){
condition_1 true-block;
...
}
else if(condition_2){
condition_2 true-block;
condition_1 false-block too;
...
}
23

24. switch statement in java
 Using the switch statement, one can select only one
option from more number of options very easily.
 In the switch statement, we provide a value that is to be
compared with a value associated with each option.
 Whenever the given value matches the value associated
with an option, the execution starts from that option.
 In the switch statement, every option is defined as
a case.
24

25. 25

26. loop
 while loop
-used to repeat a given statement over and over.
-entry controlled
syntax:
while(boolean-expression)
{
statements
}
26

27. loop (or) iteration ->do-while statement in java
- is used to execute a single statement or block of statements
repeatedly as long as given the condition is TRUE. The do-while
statement is also known as the Exit control looping statement.
27

28. for statement
The for statement is used to execute a single statement or a
block of statements repeatedly as long as the given
condition is TRUE.
28

29. JUMP STATEMENTS IN JAVA
 The java programming language supports jump statements
that used to transfer execution control from one line to
another line. The java programming language provides the
following jump statements.
 break statement
 continue statement
 labelled break and continue statements
 return statement
 break statement in java
 The break statement in java is used to terminate a switch or
looping statement. That means the break statement is used to
come out of a switch statement and a looping statement like
while, do-while, for, and for-each.
29

30. 30

31. continue statement in java
 The continue statement is used to move the execution control to
the beginning of the looping statement.
 When the continue statement is encountered in a looping
statement, the execution control skips the rest of the statements in
the looping block and directly jumps to the beginning of the loop.
 The continue statement can be used with looping statements like
while, do-while, for, and for-each.
 When we use continue statement with while and do-while
statements, the execution control directly jumps to the condition
 When we use continue statement with for statement the execution
control directly jumps to the modification portion
(increment/decrement/any modification) of the for loop.
31

32. 32

33. Empty statement
 Consists simply of a semicolon(;)
if(x<0)
{
x=-x;
}; legal –presence of the semicolon the compiler
considers it to be an empty statement, not part of the if
statement.
33

34. Arrays
 Arrays are data structures that hold data of the same type
in contiguous memory.
 A group of memory cells that are contiguous have same
name and store the same data type.
 Two types
 One dimensional
 Multidimensional
34

35. Declaring Array Variables
 To use an array in a program, must declare a variable to
reference the array, and must specify the type of array
the variable can reference
Syntax
Int age[ ];
double score[ ];
35

36. Creating Arrays
Allocation of memory and initialization
create an array by using the new operator with the following
syntax −
Syntax
arrayRefVar = new dataType[arraySize];
age= new int[ 10];
The above statement does two things −
 It creates an array using new dataType[arraySize].
 It assigns the reference of the newly created array to the variable
arrayRefVar.
36

37. Declaring an array variable, creating an array, and assigning the reference
of the array to the variable can be combined in one statement, as shown
below −
dataType[] arrayRefVar = new dataType[arraySize];
 Alternatively you can create arrays as follows −
dataType[] arrayRefVar = {value0, value1, ..., valuek};
The array elements are accessed through the index. Array indices are 0-
based; that is, they start from 0 to arrayRefVar.length-1.
37

38. Representation of
one dimensional array

38

39. Multidimensional array
 Can be used to represent tables of data
 It has rows and columns and two subscripts are needed to access the array elements.
 (m-rows & n-column ie. m x n array)
Syntax
 int arrayofnum[ i] [j ];
 arrayname[ i] [j ]=value;
 int[ ] [ ] arrayofnum={{12,12,3},{45,8,90}};
data_type[dimension 1][dimension 2][]…[dimension n] = new data_type[size 1][size 2]…[size n]
 example
int[][] array1 = new int[2][2];//Two dimensional Integer Array with 2 rows and 2 columns
Three Dimensional Array’s Declaration
int[][][] array2 = new int[12][24][36]; //Three dimensional Array
39

40. Strings
 Represents group of characters
 Strings written in java program are all String class objects.
 String class objects are immutable
 Java defines the String class , which is part of
java.lang.package
40

41. Constructor of string class
String (char array[]);
 String (char array[], int start, int count);
 String (String object);
 Constructor of String class with byte array
 String(byte a[]);
 String (byte a[], int start, int count);
Special type of constructor
 String(StringBuffer a[]);
41

42. Methods of String class
 Char charAt(int index)
 Void getChars()
 Byte[] getBytes()
 boolean equals(String str)
 boolean equalsIgnoreCase(String str)
 int compareTo(String str)
 int compare ToIgnoreCase (String str)
 Boolean startsWith(String str)
 Boolean startsWith(String str, int index)
 Boolean endsWith(String str)
 Boolean endsWith(String str, int index)
 int indexOf(int ch)
 int indexOf(int ch, int index)
42

43.  Int lastIndexOf(int ch)
 Int lastIndexOf(int ch, int index)
 String subString(int index)
 String subString(int index1,int index2)
 String concat(String str)
 String replace(char oldcharacter,char newcharacter)
 String trim()
 String toLowerCase()
 String toUpperCase()
 Int length()
43

44.  valueOf() method
 The java string valueOf() method converts different types of
values into string. By the help of string valueOf() method, you
can convert int to string, long to string, boolean to string,
character to string, float to string, double to string, object to
string and char array to string.
 equals() method
 The java string equals() method compares the two given strings
based on the content of the string. If any character is not
matched, it returns false. If all characters are matched, it returns
true. The String equals() method overrides the equals()
method of Object class.

44

45. StringBuffer class
 Java provides a class called StringBuffer.
 StringBuffer is a mutable string, which can be changed
during the execution of a program.
 Changeable of set of character
StringBuffer();
StringBuffer(int size):
StringBuffer(String str);
45

46. Constructor Description
StringBuffer() creates an empty string
buffer with the initial
capacity of 16.
StringBuffer(String str) creates a string buffer with
the specified string.
StringBuffer(int capacity) creates an empty string
buffer with the specified
capacity as length.
46

47.  StringBuffer append(int value)
 StringBuffer append(char[] str, int start,int length)
 Int capacity()
 StringBuffer delete()
 StringBuffer insert()
 StringBuffer reverse()
 Void setCharAt(int index,char ch)
 Void setLength(int size)
47

48.  1) StringBuffer append() method
 The append() method concatenates the given argument with this string.
class StringBufferExample{
public static void main(String args[]){ StringBuffer sb=new StringBuffer("Hello "); sb.appen
d("Java");//now original string is changed
System.out.println(sb);//prints Hello Java
}
}
48

49.  StringBuffer insert() method
 The insert() method inserts the given string with this string at
the given position.
class StringBufferExample2
{
public static void main(String args[])
{ StringBuffer sb=new StringBuffer("Hello ");
sb.insert(1,"Java");//now original string is changed
System.out.println(sb);//prints HJavaello
}
}
49

50.  3) StringBuffer replace() method
 The replace() method replaces the given string from the
specified beginIndex and endIndex.
 class StringBufferExample3{
 public static void main(String args[]){ StringBuffer sb=n
ew StringBuffer("Hello"); sb.replace(1,3,"Java");
 System.out.println(sb);//prints HJavalo
 }
 }
50

51.  4) StringBuffer delete() method
 The delete() method of StringBuffer class deletes the
string from the specified beginIndex to endIndex.
 class StringBufferExample4{
 public static void main(String args[]){ StringBuffer sb=n
ew StringBuffer("Hello"); sb.delete(1,3);
 System.out.println(sb);//prints Hlo
 }
 }
51

52.  5) StringBuffer reverse() method
 The reverse() method of StringBuilder class reverses the
current string.
 class StringBufferExample5{
 public static void main(String args[]){ StringBuffer sb=n
ew StringBuffer("Hello"); sb.reverse();
 System.out.println(sb);//prints olleH
 }
 }
52

53.  6) StringBuffer capacity() method
 The capacity() method of StringBuffer class returns the current capacity of the buffer. The
default capacity of the buffer is 16. If the number of character increases from its current
capacity, it increases the capacity by (oldcapacity*2)+2. For example if your current capacity is
16, it will be (16*2)+2=34.
 class StringBufferExample6{
 public static void main(String args[]){ StringBuffer sb=new StringBuffer(); System.out.printl
n(sb.capacity());//default 16
 sb.append("Hello");
 System.out.println(sb.capacity());//now 16
 sb.append("java is my favourite language");
 System.out.println(sb.capacity());//now (16*2)+2=34 i.e (oldcapacity*2)+2
 }
 }
53

54. Method Description
char charAt(int index) returns char value for the
particular index
int length() returns string length
static String format(String format,
Object... args)
returns a formatted string.
static String format(Locale l, String
format, Object... args)
returns formatted string with given
locale.
String substring(int beginIndex) returns substring for given begin
index.
String substring(int beginIndex, int
endIndex)
returns substring for given begin
index and end index.
boolean contains(CharSequence s) returns true or false after matching
the sequence of char value.
static String join(CharSequence
delimiter, CharSequence... elements)
returns a joined string.
54

55. static String join(CharSequence
delimiter, Iterable<? extends
CharSequence> elements)
returns a joined string.
boolean equals(Object another) checks the equality of
string with the given
object.
boolean isEmpty() checks if string is empty.
String concat(String str) concatenates the specified
string.
String replace(char old, char
new)
replaces all occurrences of
the specified char value.
String replace(CharSequence
old, CharSequence new)
replaces all occurrences of
the specified
CharSequence.
static String
equalsIgnoreCase(String
another)
compares another string.
It doesn't check case.
String[] split(String regex) returns a split string
matching regex.
55

56. String[] split(String regex,
int limit)
returns a split string
matching regex and limit.
String intern() returns an interned string.
int indexOf(int ch) returns the specified char value
index.
int indexOf(int ch, int
fromIndex)
returns the specified char value
index starting with given index.
int indexOf(String substring) returns the specified substring
index.
int indexOf(String substring, int
fromIndex)
returns the specified substring
index starting with given index.
String toLowerCase() returns a string in lowercase.
String toLowerCase(Locale l) returns a string in lowercase
using specified locale.
String toUpperCase() returns a string in uppercase.
String toUpperCase(Locale l) returns a string in uppercase
using specified locale.
String trim() removes beginning and ending
56

57. THANK YOU
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