Download Java - IBM

About Us: Strongback Consulting
• IBM Advanced Business Partner
– Rational, WebSphere, Lotus, Information Management SVP certified
– Strongly focused on Enterprise Modernization, Agile Transformations, and DevOps
– Key Industries Served: Finance, Insurance, Healthcare, Manufacturing, Government
– Rational Design Partner for HATS and other Rational enterprise modernization
technologies
Discover us at:
http://www.strongback.us
Subscribe to us at
http://blog.strongbackconsulting.com
Socialize with us on Facebook & LinkedIn
http://www.facebook.com/StrongbackConsulting
http://www.linkedin.com/company/290754
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Your Instructor
• Kenny Smith
– Principal Consultant @ Strongback Consulting
– Developed courses for multiple Rational IDE’s
– Past speaker at IBM’s RSDC, Innovate, and
InterConnect, and N. FL Rational User Group
– Major projects: Multiple RDz rollouts, several large
systems modernizations, many custom development
gigs
– Languages: Java, COBOL, VB, HTML, XML, SQL,
JavaScript, Perl, Python, JACL
– http://about.me/smithkenny
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What is Java?
• Platform neutral programming language
• Concurrent, class-based, and object oriented
• Most similar to C/C++ syntax
• Compiled into bytecode, which is run by a Java Virtual Machine
– Write once, run anywhere
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Why Java on System z?
 Abundance of Java and Java skills
 zAAP Processors - cost effective
workload management
 Combining of traditional batch with
modern frameworks
 Access to MVS using the JZOS API
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Abundance of Java
• #1 Programming language – Tiobe– September 2015
– C ranks #2 (frequently trades places with Java)
– COBOL ranks #20
– Assembler ranks #11
• Ubiquity of architectural frameworks
– Unit testing, relational object mapping, security, dependency injection, etc.
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Java Frameworks
Don't reinvent
the wheel, just
realign it.
Anthony J.
D'Angelo, The College
Blue Book
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zAAP Processors – Cost Effective Solution
• A specialty z processor engine
• Attractively priced execution environment for web apps
• Simplifies and reduces server infrastructures
• Maximizes the value of your mainframe investments
• Lowers the overall cost of computing for WebSphere Application Server and
other Java
• JIT on the z has greatly increased performance on the z.
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Where does Java run?
• The JVM runs in Unix System Services (USS)
• Source code can be compiled anywhere
• Class and jar files written to USS directories for running in the JVM
• Workloads on Java are qualified to run on zAAP processor
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z/OS UNIX with Open Systems Interfaces
z/OS
API
(C Functions)
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Language Environment
(LE)
Interactive Shell
(commands)
HFS
zFS
zFS
WLM
UNIX
System
Services
SMF
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z/OS Unix Files
• Found in Remote Systems View
• z/OS Unix Files section
– Home = your home folder in OMVS
• Typically /u/username
– Root = / (zFS system root folder)
– Filters = everything else
• You specify the settings for the filter
• z/OS Unix shells
– Open one or more Unix shells
– Each shell separate from each other
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How do I Write Java?
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RAD And Java
• Like RDz, built on Eclipse
• Can “shell share” with RDz, providing more features than either alone
– CICS Web Service Development
– Can also shell share with Data Studio
• Highly effective editors, wizards, and visualization tools
• Includes Java code review tools (Software Analyzer)
• Designed to handle Java EE development
– Wizards for web development (JSF, JSP, Struts, etc.)
– Database development (SQL editors, JPA wizards)
– WebSphere Application Server environment
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RDz Enterprise Tools: Unit Testing
JUnit: A unit test framework for Java
• Built into RAD / Eclipse
• Tests either pass or fail
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RDz Enterprise Tools: Software Analysis
• Allows you to run a static analysis of the resources with which you are
working to detect violations of rules and rule categories.
• Detects violations of specific programming rules and rule categories and
generates a report in the Software Analyzer Results view
• Code can be viewed in a single interface to analyze each component in a
multi-language application…. Java, Cobol and others.
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Rational Developer for the Enterprise 9.5
Rational Developer for the Enterprise
Rational
Application
Developer for
WebSphere
Software 9.0
Rational
Developer for
System z 9.5
Rational
Business
Developer 9.5
Rational Developer
for i 9.5
Rational
Developer for
AIX and Linux
9.5
Rational
Application
Developer
Rational
Developer for
System z
Rational Business
Developer
RPG and COBOL Tools
C/C++ Edition
RPG and COBOL +
Modernization Tools, Java
Edition
AIX COBOL
Edition
RPG and COBOL +
Modernization Tools, EGL
Edition
Rational Business Developer
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Comparing Language Features
Java
COBOL
• Portable – write once run
anywhere
• Syntax specific to compiler (IBM
vs Microfocus, etc.)
• Object Oriented
• Procedural
• Connect to CICS via web services
• Call CICS directly
• No binding of DB2 required
• Must bind DB2
• Not column sensitive (> 80 chars)
• Column sensitive
• Case Sensitive
• Not case sensitive
• Strongly typed
• Considered non-typed
• Can be multi-threaded
• Single threaded
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Unique Java Language Features
• Object oriented: Polymorphism, Inheritance, Composition, Encapsulation
• Garbage Collection: automated memory management
• Secure
• Interpreted: compiled to bytecode, and bytecode executed by JVM
• Objects and Classes
• Case Sensitive!
– i.e.
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Customer != customer
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Organizing Code: Packages vs PDS
Java: Packages
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COBOL: PDS’s
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Instantiating Variables
Java
public class YieldInfo(){
COBOL
01 yield-info.
BigDecimal startBalance;
03 start-balance
pic 9(9)v9(2)
comp.
BigDecimal yield;
03 yield
pic 9(9)v9(2)
comp.
BigDecimal interest;
03 interest
pic
comp.
int days;
03 days
pic 9(9)
comp.
int years;
03 years
pic 9(2)
comp.
v9(7)
}
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Example Conversion
• COBOL Copybook
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• Java Class
Java Primitive Data Types
Data Type
Size (in bits for numeric)
Default Value (for fields)
byte
8
0
short
16
0
int
32
0
long
64
0L
float
32 floating point
0.0f
double
64 floating point
0.0d
char
16 (Unicode)
'\u0000'
boolean
1
false
Anything else is considered an Object!
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Other Common Data Types
• Integer – object wrapper for int
• Long – object wrapper for long
• Short – object wrapper for short
• String – object wrapper for char
• BigDecimal - complex object that handles currency
– NEVER EVER EVER use floating point arithmetic for currency!!!
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Typical Java Class Structure
• Package (1)
• Import statements (3)
• Class declaration (5)
• Class variables (6-8)
• Constructors (10, 13)
• Methods (20, 28)
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General Syntax
class
variable
calls the Team
default
constructor
class
name
Statements
end in
semicolon
instance
variable
name
Code blocks are
surrounded by braces
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Accessing Data, and Systems
AIX
z/OS
MQ
DB2
JDBC
Java (Batch)
Web Service
CICS
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Windows
MSSQL
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Accessing DB2 Data
• Accessing z/OS DB2 Data is no different than Java on distributed
• JPA Wizards – Java Persistence Architecture
– Makes CRUD operations a breeze!
– Hardly any SQL has to be written
• JDBC – Java Database Connectivity
– Old school SQL method
• Other open source frameworks
– iBatis, Hibernate, Spring JDBC Templates, etc.
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JZOS Java API for developers
• API = Application Programming Interface
• A framework acquired by IBM & now part of the IBM JVM
• Preferred method for MVS file access, data type conversion,
MVS Console, etc.
• Includes a batch launcher
• Uses JNI / C to access MVS datasets, VSAM files, QSAM files,
etc.
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Calling JZOS Batch
MVS
JZOS JCL
Programmer
writes and
submits the JCL
Unix System Services
MC
PDS
JZOS PROC
JZOS API
Java class
JES
JVMLDMxx
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Java Runtime
JZOS JCL Skeleton
Job Card
Location of the JVM
Proc
Execute the generic
proc with vars
Location of the
output
Java shell
environment setup
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Java Generic PROC
• A parameterized procedure makes it easier to standardize the
environment
• A sample is included in the JDK for z/OS
• Found under /usr/lpp/java/J7.0_64/mvstools/samples/jcl
– Good for most usage, customize for a given specific instance
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Approaches to Java Batch
WebSphere Batch
z/OS Batch Container
JZOS JVM Launcher
• JCL launches batch
program
• Programmer may still
need to code
functions not
provided by Launcher
• Example is z/OS
Batch Container
• Batch Container
provides useful
functions
• Programmer may
still need to code
functions not
provided by
Container
• Example is IBM
WebSphere Compute
Grid
• Provides batch
programming
function as services
of the platform
• Allows programmer
to focus on the
business logic and
not develop "custom
middleware" function
Robust
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Tools for Modern Java Batch
(aka ComputeGrid)
Workbench:
Has Capability? (Y, N, Partial)
RAD
WDT
Eclipse
Y
N
N
• Brings compute and data intensive batch processing to WAS, sharing the
same business logic used by online systems.
• Framework and tools make writing, running and managing batch
applications a snap.
• Java EE based packaging and deployment.
Batch workspace project
xJCL
App
• Projects, wizards and editors streamline the
development of xJCL and batch classes.
• Deploy and submit to WAS, with job progress
integrated into the IDE’s console.
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Scheduler
WAS
Container
WAS
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Where Can I Learn More?
• Strongback Consulting’s Course Offerings:
– RDz COBOL, RDz Java (JZOS), RAD, HATS
• Our blog http://blog.strongbackconsulting.com
• All our JZOS specific links: https://delicious.com/strongback/search/jzos
• Rational software links: https://delicious.com/strongback/search/rational
• Java generic links: https://delicious.com/strongback/search/java
*** Delicious.com is a bookmark sharing site. It may be blocked by your IT department, but
allows us to share more links than we have room to list here
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Subscribe to us at
http://feeds.feedburner.com/StrongbackConsulting
Discover us at:
http://www.strongback.us
Socialize with us on Facebook & LinkedIn
http://www.facebook.com/StrongbackConsulting
http://www.linkedin.com/company/290754
Watch Us at Youtube http://www.youtube.com/user/strongbackconsulting
https://vimeo.com/user7519232
Call us at: 386-232-8746
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Class API Overview:
• Access MVS Datasets
– com.ibm.jzos.Zfile – thin wrapper for JNI calls to C I/O library
– com.ibm.jzos.FileFactory - platform-portable file access
• Access HFS/zFS files
– java.io, java.nio – standard Java API
– com.ibm.jzos.FileFactory
• Access the MVS Console
– com.ibm.jzos.MvsConsole – interface to MVS console and job log
• Various z/OS native functions
– com.ibm.jzos.ZUtil
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Calling Java in batch
• BPXBATCH
– The “original” batch java caller.
– Best to run non-Java shell commands on Unix System Services
– The STDOUT and STDERR DD names are not allocated as MVS data sets
• JZOS
– The modern batch caller
– Uses a specific JVM load module
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JZOS Batch
• Jobs are zAAP eligible
• IDE Integration with RDz, RAD
• Can run Java based servers as started tasks
• Full integration into the Job Entry System
• Jobs run in the same address space
• Support for DD statements
• Move stdin, stdout, and stderr to an MVS Dataset
• Gives a valid return code (other than just 1)
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