Java packages and dependency

When java was being developed, what was the philosophy behind allowing packages to be mutually dependent?

Hello Steve,
The Acyclic Dependencies Principle tells us that no cycles should exit in a model depicting the dependencies between packages. From what I can gather this is useful when developing large software systems, as each package becomes a viable work unit for an engineer or small group of engineers to control as a series of releases. If the ADP is not complied with, cycles may exist in the dependencies between packages. If a change is made to one of those packages within a cycle, then an ugly situation develops as the repercussions of the change are looped through the cycle back to its source and so on.
The thing is though, during my readings I came across a statement that said Java packages were mutually dependent. I was just wanting to know why a language that utilises object oriented technology, left the practice of the ADP up to the descretion of the developer? Is the full implementation of ADP on a software system an ideal world scenario?
Anders.

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JAVA PACKAGES and JSP

i Have two problems one is i am designing a website which consists of a form. I am trying to write the Connectiviy and all other insert statements in seperate java packages and include them in JSP files.
i Have two java packages one is DBUtil(having two java files both dealing with connectovity) and another one is StudentUtIl which has java files that open the connections with database connection and insert data into DB., I am having a big Problem here. How can i call the function in the other java package in the files in this java package. i have openDB()and Close() in the other Db and i want to call these functions in JAVA classes in the other package. How to include a package. Both these packages are in the same File system mounted on a Local directory

Thank you for the reply. I am giving the code i have given the full class name . and now it is giving the following error :
Cannot reference a non-static method connectDB() in a static context.
I am also giving the code. Please do help me on this. i am a beginner in java.
import java.sql.*;
import java.util.*;
import DButil.*;
public class StudentManager {
/** Creates a new instance of StudentManager */
public StudentManager() {
Connection conn = null;
Statement cs = null;
public Vector getStudent(){
try{
dbutil.connectDB();
String Query = "Select St_Record, St_L_Name, St_F_Name, St_Major, St_Email_Address, St_SSN, Date, St_Company, St_Designation";
cs = conn.createStatement();
java.sql.ResultSet rs = cs.executeQuery(Query);
Vector Studentvector = new Vector();
while(rs.next()){
Studentinfo Student = new Studentinfo();
Student.setSt_Record(rs.getInt("St_Record"));
Student.setSt_L_Name(rs.getString("St_L_Name"));
Student.setSt_F_Name(rs.getString("St_F_Name"));
Student.setSt_Major(rs.getString("St_Major"));
Student.setSt_Email_Address(rs.getString("St_Email_Address"));
Student.setSt_Company(rs.getString("St_Company"));
Student.setSt_Designation(rs.getString("St_Designation"));
Student.setDate(rs.getInt("Date"));
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if( cs != null)
cs.close();
if( conn != null && !conn.isClosed())
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return Studentvector;
}catch(Exception ignore){
return null;
}finally {
dbutil.closeDB();
import java.sql.*;
import java.util.*;
public class dbutil {
/** Creates a new instance of dbutil */
public dbutil() {
Connection conn;
public void connectDB(){
conn = ConnectionManager.getConnection();
public void closeDB(){
try{
if(conn != null && !conn.isClosed())
conn.close();
}catch(Exception excep){
The main error is occuring at the following lines connectDB() and closeDB() in the class student manager. The class dbutil is in an another package.with an another file called connectionManager which establishes the connection with DB. The dbutil has the openconnection and close connection methods. I have not yet written the insert statements in StudentManager. PLease do Help me

Java package and c++ header files

What is the difference between importing java package and including header files in c++?

I do not know .. have been away from C/C++ for a long time...
As much as I remember you can only import one header file each time... also when you import a header file you can just call methods from the header file automatically ...
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Sim085

To know abt java packages and classes

please give an idea abt how to find the list of packages and classes
available in the java packages

Which ones? If you mean the ones available in the standard Java APIs, check the java-docs:
1.4.2:
http://java.sun.com/j2se/1.4.2/docs/api/
1.5:
http://java.sun.com/j2se/1.5.0/docs/api/

2 files in same package and depends each other need import package??

test1.java and test2.java are in the same package mypackage,
and test1.java will call methods in test2.java, does it mean
test1.java needs to import mypackage.test2;
i.e.
//test1.java
package mypackage;
import mypackage.test2;
class test1
}

no, once classes are in the same packages they are picked up ie tc1 is in tc_package and tc2 is also in tc_package, tc1 need not import tc_package.tc2 to use tc2 methods.
/Paul

Java Package/Class Dependency

Hi, friends,
I would like to get a list of packages that a given package depends on. If it is possible, I would also know which class of the given package depends on which classes.
Is there any software to do this?
If I would like to write a Java utility for that purpose, how can I proceed?
Best regards,
Youbin

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java.lang.Object
|
--java.awt.Component
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--javax.swing.JComponent
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ImageObserver, MenuContainer, Serializable
Direct Known Subclasses:
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vincent

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Hi,
I have 2 java classes
A.java
B.java
### A.java ###
import B;
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'.' expected
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Thanks in advance.
NP

- the default package (the package with no name)It does? Not for me.Gosh, you're right, it doesn't. Sorry.
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Packages and packages

Hi
I was rereading Martin's principles of package architecture and was wondering how the concept of package in this context relates to the concept of a Java package
after thinking a bit, I got the feeling these two concepts have nothing to do with each other
I feel that Java packages deal with namespace and access control, while OO packages (the components of your program's binaries) would be, in the Java world, jar files containing classes from different packages (and not especially all classes from these (Java) packages), and constructed as much as possible in order to follow these supposedly good OO principles
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dataaccess
business
web
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Creating Packages and Namespace for Webdynpro Java applications in NWDS

Hi Experts,
I am working on a stand alone application and using NWDS for the same. This application consist of some Webdynpro Java apps, Dictionary perspective DC's and BPM applications.
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HI,
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https://www.sdn.sap.com/irj/sdn/go/portal/prtroot/docs/library/uuid/419b479b-0801-0010-f8a1-c26208b4b209
http://help.sap.com/saphelp_nw70/helpdata/en/44/60dc1943c2311ce10000000a155369/frameset.htm
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Hi,
I am just starting out with java and have reached the stage where I want to store my files in packages and the correct directory structure. I have read through the sun link below and have a question they seam to miss. They say that .java and .class files should be kept in separate places. ie sources and classes directories with the package directory names below. But I have found that unless you have the .class files you are referencing in the same directory as the .java files when you come to compile you will get an error so they have to be stored in the same directory???.. Does this make sence or have I gotten it all wrong.
Thanks
Joolz
http://java.sun.com/docs/books/tutorial/java/interpack/managingfiles.html

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Hi everybody,
I'm bearly new on Java-JSP developping and I wanted to know how Tomcat (for example) manage the imported packages and classes.
The fact is I'm working on a project ('/bob') which use some packages that I don't see in the '/bob' directory. So, is that possible that '/bob' is downloading packages and classes from Internet to '/bob/download' virtual repertory and use it? If it is true, is it possible to override this download by making '/bob' project using local packages or classes (example : com.boblibrary.classes.util in '/bob/WEB-INF/classes/com/boblibrary/classes/util') instead of downloading it?
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[svn:bz-trunk] 10059: update two package-info.java files, and add one new one.

Revision: 10059
Author:   [email protected]
Date:     2009-09-08 11:31:48 -0700 (Tue, 08 Sep 2009)
Log Message:
update two package-info.java files, and add one new one.
Modified Paths:
    blazeds/trunk/modules/proxy/src/flex/messaging/services/http/proxy/package-info.java
Added Paths:
    blazeds/trunk/modules/core/src/flex/messaging/util/concurrent/package-info.java
    blazeds/trunk/modules/core/src/flex/messaging/validators/package-info.java

Revision: 10059
Author:   [email protected]
Date:     2009-09-08 11:31:48 -0700 (Tue, 08 Sep 2009)
Log Message:
update two package-info.java files, and add one new one.
Modified Paths:
    blazeds/trunk/modules/proxy/src/flex/messaging/services/http/proxy/package-info.java
Added Paths:
    blazeds/trunk/modules/core/src/flex/messaging/util/concurrent/package-info.java
    blazeds/trunk/modules/core/src/flex/messaging/validators/package-info.java

How to use " toFront() " method in java application and in which package or

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The API documentation has a link at the top of every page that says "Index". If you follow that and look for toFront(), you will find it exists in java.awt.Window and javax.swing.JInternalFrame.
To use it in a Java application, create an object x of either of those two classes and write "x.toFront();".

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Java packages and dependency

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