The document discusses advanced features of Java, including Java Beans, exception handling, generics, Java Database Connectivity (JDBC), and the Java Collections Framework. It provides definitions, examples, and code snippets to illustrate these concepts, showing how they enhance Java's functionality and programming efficiency. Additionally, the document highlights local Java user groups and upcoming events for further learning and community engagement.

1. 1
Java Advanced
Features
Trenton Computer Festival
March 17, 2018
Michael P. Redlich
@mpredli
about.me/mpredli/

2. Who’s Mike?
• BS in CS from
• “Petrochemical Research Organization”
• Java Queue News Editor, InfoQ
• Ai-Logix, Inc. (now AudioCodes)
• Amateur Computer Group of New Jersey
2

3. Objectives (1)
• Java Beans
• Exception Handling
• Generics
• Java Database Connectivity
• Java Collections Framework
3

4. Java Beans
4

5. What are Java Beans?
• A method for developing reusable Java
components
• Also known as POJOs (Plain Old Java Objects)
• Easily store and retrieve information
5

6. Java Beans (1)
• A Java class is considered a bean when it:
• implements interface Serializable
• defines a default constructor
• defines properly named getter/setter methods
6

7. Java Beans (2)
• Getter/Setter methods:
• return (get) and assign (set) a bean’s data
members
• Specified naming convention:
•getMember
•setMember
•isValid
7

8. 8
// PersonBean class (partial listing)
public class PersonBean implements Serializable {
private static final long serialVersionUID = 7526472295622776147L;
private String lastName;
private String firstName;
private boolean valid;
public PersonBean() {
}
public String getLastName() {
return lastName;
}
public void setLastName(String lastName) {
this.lastName = lastName;
}
// getter/setter for firstName
public boolean isValid() {
return valid;
}
}

9. Demo Time…
9

10. Exception Handling
10

11. What is Exception
Handling?
• A more robust method for handling errors
than fastidiously checking for error codes
• error code checking is tedious and can obscure
program logic
11

12. Exception Handling (1)
• Throw Expression:
• raises the exception
• Try Block:
• contains a throw expression or a method that
throws an exception
12

13. Exception Handling (2)
• Catch Clause(s):
• handles the exception
• defined immediately after the try block
• Finally Clause:
• always gets called regardless of where exception
is caught
• sets something back to its original state
13

14. Java Exception Model
(1)
• Checked Exceptions
• enforced by the compiler
• Unchecked Exceptions
• recommended, but not enforced by the compiler
14

15. Java Exception Model
(2)
• Exception Specification
• specify what type of exception(s) a method will
throw
• Termination vs. Resumption semantics
15

16. 16
// ExceptionDemo class
public class ExceptionDemo {
public static void main(String[] args) {
try {
initialize();
}
catch(Exception exception) {
exception.printStackTrace();
}
public void initialize() throws Exception {
// contains code that may throw an exception of type Exception
}
}

17. Demo Time…
17

18. Generics
18

19. What are Generics?
• A mechanism to ensure type safety in Java
collections
• introduced in Java 5
• Similar concept to C++ Template
mechanism
19

20. Generics (1)
• Prototype:
• visibilityModifier class |
interface name<Type> {}
20

21. 21
// Iterator demo *without* Generics...
List list = new ArrayList();
for(int i = 0;i < 10;++i) {
list.add(new Integer(i));
}
Iterator iterator = list.iterator();
while(iterator.hasNext()) {
System.out.println(“i = ” + (Integer)iterator.next());
}

22. 22
// Iterator demo *with* Generics...
List<Integer> list = new ArrayList<Integer>();
for(int i = 0;i < 10;++i) {
list.add(new Integer(i));
}
Iterator<Integer> iterator = list.iterator();
while(iterator.hasNext()) {
System.out.println(“i = ” + iterator.next());
}

23. 23
// Defining Simple Generics
public interface List<E> {
add(E x);
}
public interface Iterator<E> {
E next();
boolean hasNext();
}

24. Java Database
Connectivity (JDBC)
24

25. What is JDBC?
• A built-in API to access data sources
• relational databases
• spreadsheets
• flat files
• The JDK includes a JDBC-ODBC bridge for
use with ODBC data sources
• type 1 driver
25

26. Java Database
Connectivity (1)
• Install database driver and/or ODBC driver
• Establish a connection to the database:
• Class.forName(driverName);
• Connection connection =
DriverManager.getConnection();
26

27. Java Database
Connectivity (2)
• Create JDBC statement:
•Statement statement =
connection.createStatement();
• Obtain result set:
• Result result =
statement.execute();
• Result result =
statement.executeQuery();
27

28. 28
// JDBC example
import java.sql.*;
public class DatabaseDemo {
public static void main(String[] args) {
String sql = “SELECT * FROM timeZones”;
Class.forName(“sun.jdbc.odbc.JdbcOdbcDriver”);
Connection connection =
DriverManager.getConnection(“jdbc:odbc:timezones”,””,””);
Statement statement = connection.createStatement();
ResultSet result = statement.executeQuery(sql);
while(result.next()) {
System.out.println(result.getDouble(2) + “ “
+ result.getDouble(3));
}
connection.close();
}
}

29. Java Collections
Framework
29

30. What are Java
Collections? (1)
• A single object that groups together
multiple elements
• Collections are used to:
• store
• retrieve
• manipulate
30

31. What is the Java
Collection Framework?
• A unified architecture for collections
• All collection frameworks contain:
• interfaces
• implementations
• algorithms
• Inspired by the C++ Standard Template
Library
31

32. What is a Collection?
• A single object that groups together
multiple elements
• sometimes referred to as a container
• Containers before Java 2 were a
disappointment:
• only four containers
• no built-in algorithms
32

33. Collections (1)
• Implement the Collection interface
• Built-in implementations:
• List
• Set
33

34. Collections (2)
• Lists
• ordered sequences that support direct
indexing and bi-directional traversal
• Sets
• an unordered receptacle for elements
that conform to the notion of
mathematical set
34

35. 35
// the Collection interface
public interface Collection<E> extends Iterable<E>{
boolean add(E e);
boolean addAll(Collection<? extends E> collection);
void clear();
boolean contains(Object object);
boolean containsAll(Collection<?> collection);
boolean equals(Object object);
int hashCode();
boolean isEmpty();
Iterator<E> iterator();
boolean remove(Object object);
boolean removeAll(Collection<?> collection);
boolean retainAll(Collection<?> collection);
int size();
Object[] toArray();
<T> T[] toArray(T[] array);
}

36. Iterators
• Used to access elements within an ordered
sequence
• All collections support iterators
• Traversal depends on the collection
• All iterators are fail-fast
• if the collection is changed by something other
than the iterator, the iterator becomes invalid
36

37. 37
// Iterator demo
import java.util.*;
List<Integer> list = new ArrayList<Integer>();
for(int i = 0;i < 9;++i) {
list.add(new Integer(i));
}
Iterator iterator = list.iterator();
while(iterator.hasNext()) {
System.out.println(iterator.next());
}
0 1 2 3 4 5 6 7 8
current last

38. Demo Time…
38

39. Java IDEs (1)
• IntelliJ IDEA 2017.3
•jetbrains.com/idea
• stay tuned for version 2018.1 coming soon
• Eclipse IDE
•eclipse.org/ide
39

40. Java IDEs (2)
• NetBeans 8.2
•netbeans.org
• currently being moved from Oracle to Apache
40

41. Local Java User Groups
(1)
• ACGNJ Java Users Group
• facilitated by Mike Redlich
• javasig.org
• Princeton Java Users Group
• facilitated byYakov Fain
• meetup.com/NJFlex
41

42. Local Java User Groups
(2)
• NYJavaSIG
• facilitated by Frank Greco
• javasig.com
• PhillyJUG
• facilitated by Martin Snyder, et. al.
• meetup.com/PhillyJUG
42

43. Local Java User Groups
(3)
• Capital District Java Developers Network
• facilitated by Dan Patsey
•cdjdn.com
• currently restructuring
43

44. Further Reading
44

45. Upcoming Events
• ACGNJ Java Users Group
• Dr. Venkat Subramaniam
• Monday, March 19, 2018
• DorothyYoung Center for the Arts, Room 106
• Drew University
• 7:30-9:00pm
• “Twelve Ways to Make Code Suck Less”
45

46. 46
Thanks!
mike@redlich.net
@mpredli
redlich.net
slideshare.net/mpredli01
github.com/mpredli01

47. Upcoming Events
• March 17-18, 2017
•tcf-nj.org
• April 18-19, 2017
•phillyemergingtech.com
47