This Webinar explores a variety of new and updated features in Java 8, and discuss how these changes can positively impact your day-to-day programming. Watch the video replay here: http://bit.ly/1vStxKN Your Webinar presenter, Marnie Knue, is an instructor for Develop Intelligence and has taught Sun & Oracle certified Java classes, RedHat JBoss administration, Spring, and Hibernate. Marnie also has spoken at JavaOne.

1. What's New in Java SE 8
A Quick Look at the Platform Enhancements
1

2. Objectives
When we are done, you should be able to use:
Functional interfaces
Default methods
Lambdas and lambda expressions
java.time package
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3. Functional Interfaces
Interface containing only one method
Can annotate with java.lang.FunctionalInterface
If only one method, the annotation is not needed
Primarily used as targets for lambdas
Several have been pre-defined in
java.util.function
Predicate – used for tests; takes an argument, compares it to
the given Predicate
Function – takes an argument, returns response
Consumer – takes an argument, returns nothing
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4. Default Methods
Specialized methods found in interfaces
Marked with default keyword
Allows us to add methods to an interface long after it has
been released without breaking the interface
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@FunctionalInterface
public interface Predicate<T> {
public boolean test();
default Predicate<T> and(Predicate<? super T> other){
//do stuff
}
}

5. Lambda Expressions
Mechanism to pass functionality as an argument
Way to simplify reading of code
Anonymous inner classes tend to be bulky
Multiple functionality options decrease DRY properties and/or
cause explosion in number of methods
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6. Example: Customer
public class Customer {
private String firstName, surName;
private String street, city, state, postalCode;
public Customer (String firstName, String surName,
String postalCode){
this.firstName = firstName;
this.surName = surName;
this.postalCode = postalCode;
}
<all appropriate accessor, mutators and constructors
written here>
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7. Example: MailingList
public List<Customer> findBySurName(String surName){
List<Customer> tempList = new ArrayList<>();
for(Customer c : customerList){
if(c.getSurName().equals(surName)){
tempList.add(c);
}
}
return tempList;
}
We would need something like this for every search method
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8. Writing Lambdas
Consists of three parts
Comma-separated list of parameters enclosed in parentheses
Arrow →
Body of expression
If one expression, it is evaluated and result is returned
If it is a block, return statement can be explicitly defined
Sometimes contains ::
Can only be used when the Java compiler can determine
the data type
Called “Target Type”
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9. Lambda Expression: Part 1
Called method replaces all the various options
public List<Customer> findCustomer
(Predicate<Customer> tester){
List<Customer> customer = new ArrayList<>();
for(Customer c: customerList) {
if(tester.test(c))
customer.add(c);
}
return customer;
}
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10. Lambda Expression: Part 2
Calling method has the lambda expression
modifiedList = ml.findCustomer(c->
c.getSurName().equals("Smith") &&
c.getPostalCode().equals("12346"));
for(Customer c: modifiedList){
System.out.printf("Customer List: %s, %sn",
c.getSurName(), c.getFirstName());
});
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11. Charset Improvements
Goal
Decrease size of installed charsets
Reduce maintenance cost
Improve performance of encoding/decoding
Improved performance of String(byte[], …) and
string.getBytes()
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12. New Date-Time Package
java.time package is the base
Divided into two types
• Human – based on days, months, hours
• Machine (or continuous) – based on Unix Time
Immutable and thus thread safe
Methods perform same action in each class
Works with ISO-8601 calendar system and non-ISO calendar
systems
Designed to be more natural to use and less clumsy than
Calendar
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13. Date-Time Example
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import java.time.*;
public class DateTime {
public static void main(String[] args) {
LocalTime local = LocalTime.now();
System.out.println("The time is now " + local);
LocalTime hours = local.plusHours(5);
System.out.println("In 5 hours is will be " + hours);
int seconds = local.toSecondOfDay();
System.out.println("The total number of seconds for
today is " + seconds);
}
}

14. Date-Time Example (cont.)
The previous example has the following results:
The time is now 20:07:43.289
In 5 hours it will be 01:07:43.289
The total number of seconds since midnight is 72463
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15. java.time Package
Has two enums
DayOfWeek
Month
Continuous classes
Instant
Duration
All others are considered 'human'
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16. SelectorProvider
Abstract class whose subclasses give us access to the
various channel streams
Now have one specific to Solaris using its event port mechanism
-Djava.nio.channels.spi.SelectorProvider=
sun.nio.ch.EventPortSelectorProvider
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17. Closing
Thank you!

DevelopIntelligence
http://www.Develop
Intelligence.com

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