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A programming language is a formal constructed language designed to communicate instructions to a machine, particularly a computer. Thousands of different programming languages have been created, mainly in the computer field, and many more still are being created every year. The description of a programming language is usually split into the two components of syntax (form) and semantics (meaning). Some languages are defined by a specification document (for example, the C programming language is specified by an ISO Standard), while other languages (such as Perl) have a dominant implementation that is treated as a reference. Some languages have both, with the basic language defined by a standard and extensions taken from the dominant implementation being common.

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Hi Experts,

there are two approached to pass sheet names vaue
1st approach:

JRXlsExporter exporter = new JRXlsExporter(); exporter.setParameter( JRXlsAbstractExporterParameter.SHEET_NAMES, new String[] {"first","second","third"} ); 

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cant we pass this value as parameter in java?

this way(1st approach) i am unable to follow because i am sheduling report for a specificdate. and passing few parameter inputs as well for the same report.

sample:
Util.getParamString(stringBuilder, "GENERATEDON", Date);//similarly few more params i am passing

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2nd approach:

iam setting in the report properties like below(2nd approach): Property Name = "net.sf.jasperreports.export.xls.sheet.names.all"

 Property Value = "first/second/third"

is there any chance to pass this property value as dynamic.?

I have tried like below as not works for me

<line> 
<reportElement x="0" y="-1" width="1" height="1"> 
<propertyExpression name="net.sf.jasperreports.export.xls.sheet.name"><![CDATA[$F{course_name}]]></propertyExpression> 
</reportElement> 
</line>

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1
Exploring SharePoint 2016
LVL 12
Exploring SharePoint 2016

Explore SharePoint 2016, the web-based, collaborative platform that integrates with Microsoft Office to provide intranets, secure document management, and collaboration so you can develop your online and offline capabilities.

Constructors are not inherited:
The sub class cannot inherit constructors from its super class. Consider the following example:
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public class Super {
    protected String text;
 
    public Super(String text) {
        this.text = text;
    }
}
 
public class Sub extends Super {
 
}
We can create a new instance of Super like this:
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Super super = new Super(“Hello”);   //OK
But we cannot do the same for the Sub class:
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Sub sub = new Sub(“Hello”); //Compile error, since constructor is not inherited
The solution is to write a constructor for the sub class and call the super’s constructor, for example:
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public class Sub extends Super {
 
    public Sub(String text) {
        super(text);
    }
}

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https://www.codejava.net/java-core/the-java-language/12-rules-and-examples-about-inheritance-in-java

i wrote as below

package SuperSub;
public class Super {
    protected String text;
 
    public Super(String text) {
        this.text = text;
    }
}
 

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package SuperSub;
public class Sub extends Super {
	//Super super = new Super(“Hello”);
}

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i am getting error in line 2 of Sub class
Implicit super constructor Super() is undefined for default constructor. Must define an explicit constructor
package SuperSub;
public class Sub extends Super {

	public Sub(String text) {
		super(text);
		// TODO Auto-generated constructor stub
	}
	//Super super = new Super(“Hello”);
}

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above is fine though not sure why i cannot just have Sub empty class?
Please advise
0
package SuperThis;
public class Sub extends Super {
	/*public static void main(String[] args) {
		  super.bar();
	      this.bar();
	}*/
    public void bar() {
        System.out.println("Sub.bar()...");
    }
 
 
    public void test() {
       super.bar();
       this.bar();
    }
  
    	// Sub sub=new Sub();
    	 //   sub.test();
    
        this.test();
}

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why above code is not working
i see error as below at line 21,15
Syntax error, insert "}" to complete ClassBody

Please advise
0
The super keyword:
In Java, the superkeyword is used to access members of the super type from the sub type. For example:
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public class Super {
    protected void bar() {
        System.out.println("Super.bar()...");
    }
 
}
 
public class Sub extends Super {
    public void bar() {
        System.out.println("Sub.bar()...");
    }
 
 
    public void test() {
        super.bar();
        this.bar();
    }
}
Here, we can see that both classes have a method called bar() (overriding). Therefore, if we want to invoke the super’s version of the bar() method, the super keyword is used.
 

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super with this example not working for me
package SuperThis;
public class Sub extends Super {
	public static void main(String[] args) {
		  super.bar();
	      this.bar();
	}
    public void bar() {
        System.out.println("Sub.bar()...");
    }
 
 
    //public void test() {
       // super.bar();
        //this.bar();
   // }
        
}

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above code giving below error
Cannot use super in a static context
Cannot use this in a static context

how to fix this
package SuperThis;

public class Test {
public static void main(String[] args) {
	 Sub sub=new Sub();
	    sub.test();
}
}

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Super.bar()...
Sub.bar()...


does it need separate class for this to test
package SuperThis;
public class Sub extends Super {
	/*public static void main(String[] args) {
		  super.bar();
	      this.bar();
	}*/
    public void bar() {
        System.out.println("Sub.bar()...");
    }
 
 
    public void test() {
       super.bar();
       this.bar();
    }
  
    	// Sub sub=new Sub();
    	 //   sub.test();
    
        test();
}

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how to test in same Sub class

above gives error at line 20
Multiple markers at this line
      - This method requires a body instead of a
       semicolon
      - Return type for the method is missing
      - Duplicate method test() in type Sub

please advise
0
One interesting point with inheritance in Java is that, we can use the super type when creating a new object of the sub type.
Suppose Car is the parent class of the Truck class as shown in the following code:
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public class Car {
    public void move() {
    }
}
 
public class Truck extends Car {
    public void load() {
    }
}
It’s legal to write:
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Car vehicle = new Truck();
The rule is: the type on the left side can be super type of the actual object in the right side. Note that the only methods we can invoke are the ones declared in the super type, for example:
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vehicle.move(); //okay, since Truck inherits Car
Also note that, if the subclass declares a new method, we cannot invoke it using the super type reference:
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vehicle.load(); // compile error

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IF i take parent type and object as child i am getting error.

but when i cast it as below no error

can you please advise why no error

package ParentSuperTypeObjectSubType;

public class TestClass {
	public static void main(String[] args) {
		Car vehicle = new Truck();
		vehicle.move(); //okay, since Truck inherits Car
		vehicle.load(); // compile error
		((Truck) vehicle).load(); // ok
	}

}

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below also worked fine if i cast
package ParentSuperTypeObjectSubType;

public class TestClass {
      public static void main(String[] args) {
            Car vehicle = new Truck();
            Truck car = new Car();  // Compile error
            Truck car = (Truck) new Car();  // Compile error
            vehicle.move(); //okay, since Truck inherits Car
            vehicle.load(); // compile error
            ((Truck) vehicle).load(); // ok
      }

}



is above is upcast or downcast
i confuse those similar name?
0
Remember that Java does not allow a class inherits two or more classes directly. To understand why multiple inheritance is not allowed, consider the following example:
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public class A {
    public void methodA() {
 
    }
 
    public void foo() {
 
    }
}
 
 
public class B {
    public void methodB() {
 
    }
 
    public void foo() {
 
    }
}
Suppose that we want to write a class C that extends both A and B like this:
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public class C extends A, B {
    public void methodC() {
        foo();
    }
}
As you can see, both A and B has a method called foo(), so which foo() method the class C invokes exactly? from A or B? This case is ambiguous hence Java does not allow.

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https://www.codejava.net/java-core/the-java-language/12-rules-and-examples-about-inheritance-in-java

i tried as below

package MultipleInheritance;
public class A {
    public void methodA() {
 
    }
 
    public void foo() {
 
    }
}


package MultipleInheritance;
public class B {
    public void methodB() {
 
    }
 
    public void foo() {
 
    }
}


package MultipleInheritance;
public class C extends A, B {
    public void methodC() {
        foo();
    }
}

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on C class i get below error

Multiple markers at this line
      - Syntax error on token "extends", delete this token
      - Syntax error, insert "ClassBody" to complete
       ClassDeclaration
      - Syntax error, insert "}" to complete Block

can you please advise what above error means

it did not say "multiple inheritance of state not allowed"

Please advise
0
6. Multiple inheritance of state is not allowed:
Remember that Java does not allow a class inherits two or more classes directly. To understand why multiple inheritance is not allowed, consider the following example:
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public class A {
    public void methodA() {
 
    }
 
    public void foo() {
 
    }
}
 
 
public class B {
    public void methodB() {
 
    }
 
    public void foo() {
 
    }
}
Suppose that we want to write a class C that extends both A and B like this:
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public class C extends A, B {
    public void methodC() {
        foo();
    }
}
As you can see, both A and B has a method called foo(), so which foo() method the class C invokes exactly? from A or B? This case is ambiguous hence Java does not allow.
 
7. Multiple inheritance of type is allowed:
This means Java does allow multiple inheritance between interfaces. For example:
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public interface X {
    public void methodX();
}
 
public interface Y {
    public void methodY();
}
 
public interface Z extends X, Y {
    public void methodZ();
}
This is allowed because interfaces do not have concrete methods, thus there is no ambiguity.
Likewise, we can have a class implements multiple interfaces:
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public class Sub implements X, Y, Z {
    public void methodX() { }
 
    public void methodY() { }
 
    public void methodZ() { }
}

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if both Interface X and Interface Y has same method called methodAB what happens?



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0
Let’s look at the constructor of the Truckclass - it can access the protected field numberOfWheels and the default field name. However, it cannot access the private field age. We can write:
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Truck truck = new Truck();
truck.start();
truck.move();
But the Java compiler will complain if we try to invoke the private method test():
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truck.test();   // COMPILE ERROR, since private member is not inherited

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https://www.codejava.net/java-core/the-java-language/12-rules-and-examples-about-inheritance-in-java


i supposed to put below code in which class Car or Truck or Moveable?


public class Truck extends Car {
    public Truck() {
        numberOfWheels = 8;
        name = "Truck";
        age=10;
    }
    
    Truck truck = new Truck();
    truck.start();
    truck.move();
    
}

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or as below

public class Car extends Vehicle {
	String name;
	protected int age;
    //protected int age;
    protected int numberOfWheels = 4;
    
    public void move() {
        System.out.print("Moving by engine...");
    }

	@Override
	public void start() {
		// TODO Auto-generated method stub
		
	}

	@Override
	public void stop() {
		// TODO Auto-generated method stub
		
	}
	
	/*Truck truck = new Truck();
	truck.start();
	truck.move();*/
}

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below i cannot put as it is interface

public interface Moveable {
    public void start();
 
    public void stop();
 
    public void move();
}

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please advise
0
Don’t use a for loop with an index (or counter) variable if you can replace it with the enhanced for loop (since Java 5) or forEach (since Java 8). It’s because the index variable is error-prone, as we may alter it incidentally in the loop’s body, or we may starts the index from 1 instead of 0.
Consider the following example that iterates over an array of Strings:
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String[] names = {"Alice", "Bob", "Carol", "David", "Eric", "Frank"};
 
for (int i = 0; i < names.length; i++) {
    doSomething(names[i]);
}
As you can see, the index variable i in this for loop can be altered incidentally which may cause unexpected result. We can avoid potential problems by using an enhanced for loop like this:
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for (String aName : names) {
    doSomething(aName);
}
This does not only remove potential issues but also make the code cleaner and more succinct. 

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how is it possible to do for loop index modifycation?

how enhanced for loop is diferent from for each loop?

is there any case where we still has to use traditional for loop with index
please advise
0
public class CollectionsRef {
 
    private HashSet<Integer> numbers;
 
    public ArrayList<String> getList() {
 
        return new ArrayList<String>();
    }
 
    public void setNumbers(HashSet<Integer> numbers) {
        this.numbers = numbers;
    }
}
Look at the reference types which are collection implementation classes - this locks the code to work with only these classes HashSet and ArrayList. What if we want the method getList() can return a LinkedList and the method setNumbers() can accept a TreeSet?
The above class can be improved by replace the class references to interface references like this:
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public class CollectionsRef {
 
    private Set<Integer> numbers;
 
    public List<String> getList() {
        // can return any kind of List
     [b]   return new ArrayList<String>();[/b]
    }
 
    public void setNumbers(Set<Integer> numbers) {
        // can accept any kind of Set
        this.numbers = numbers;
    }
}

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can we have generic List as return type to provide more flexibility to future changes to collection implementation?
https://www.codejava.net/coding/10-java-core-best-practices-every-java-programmer-should-know
Please advise
0
Microsoft Azure 2017
LVL 12
Microsoft Azure 2017

Azure has a changed a lot since it was originally introduce by adding new services and features. Do you know everything you need to about Azure? This course will teach you about the Azure App Service, monitoring and application insights, DevOps, and Team Services.

Avoid Redundant Initialization (0-false-null)
It’s very unnecessary to initialize member variables to the following values: 0, false and null. Because these values are the default initialization values of member variables in Java. For example, the following initialization in declaration is unnecessary:
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public class Person {
    private String name = null;
    private int age = 0;
    private boolean isGenius = false;
}
This is also redundant:
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public class Person {
    private String name;
    private int age;
    private boolean;
 
    public Person() {
        String name = null;
        int age = 0;
        boolean isGenius = false;
    }
}
Therefore, if you know the default initialization values of member variables, you will avoid unnecessary explicit initialization. See more here:

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i am not clear on below

This is also redundant:


does it mean initialization in the constructor as well apart from at class level

public Person() {
        String name = null;
        int age = 0;
        boolean isGenius = false;
    }
}

https://www.codejava.net/coding/10-java-core-best-practices-every-java-programmer-should-know
Please advise
0
It’s a very bad idea to create an interface which is solely for declaring some constants without any methods. Here’s such an interface:
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public interface Color {
    public static final int RED = 0xff0000;
    public static final int BLACK = 0x000000;
    public static final int WHITE = 0xffffff;
}
It’s because the purpose of interfaces is for inheritance and polymorphism, not for static stuffs like that. So the best practice recommends us to use an enum instead. For example:
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public enum Color {
    BLACK, WHITE, RED
}
In case the color code does matter, we can update the enum like this:
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public enum Color {
 
    BLACK(0x000000),
    WHITE(0xffffff),
    RED(0xff0000);
 
    private int code;
 
    Color(int code) {
        this.code = code;
    }
 
    public int getCode() {
        return this.code;
    }
}

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what is the meaning of color code does not matter and updating like below?

In case the color code does matter, we can update the enum like this:
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public enum Color {
 
    BLACK(0x000000),
    WHITE(0xffffff),
    RED(0xff0000);
 
    private int code;
 
    Color(int code) {
        this.code = code;
    }
 
    public int getCode() {
        return this.code;
    }
}

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https://www.codejava.net/coding/10-java-core-best-practices-every-java-programmer-should-know

when we create special AppConstants class?
can there be interface just for constants?
please advise
0
String sql = "Insert Into Users (name, email, pass, address)";
sql += " values ('" + user.getName();
sql += "', '" + user.getEmail();
sql += "', '" + user.getPass();
sql += "', '" + user.getAddress();
sql += "')"[b][u];[/u][/b]

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in above StringBuilder example why ; is not in double quotes?
https://www.codejava.net/coding/10-java-core-best-practices-every-java-programmer-should-know
https://www.w3schools.com/sql/sql_insert.asp

same question i have with StringBuilder as well
StringBuilder sbSql
    = new StringBuilder("Insert Into Users (name, email, pass, address)");
 
sbSql.append(" values ('").append(user.getName());
sbSql.append("', '").append(user.getEmail());
sbSql.append("', '").append(user.getPass());
sbSql.append("', '").append(user.getAddress());
sbSql.append("')");
 
String sql = sbSql.toString();


why we need to do toString only in case of StringBuilder

also what it mean by String builder not thread safe and string buffere thread safe

any example or link to prove this theory into practical?
Please advise
0
class Parent {
	//Parent(){}
	Parent(){}
    Parent(int number) {
    }
}
 
class Child extends Parent {
    Child(int a, int b) {
    }
}

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for above code do not i need to give  constructor as below with two arguments?


      Parent(int a, int b){}
//if i give constructor like above does it still called default constructor?

what is the meaning of below sentence?
4. The default constructor is only generated by the compiler:
If we explicitly write a constructor that looks exactly the same as the default constructor, it is NOT called the default constructor.
https://www.codejava.net/java-core/the-java-language/9-rules-about-constructors-in-java
Please advise
0
Hi,
There is list below (in Javascript) which is not being shown well. Where to identify the issue?
http://www.SearchHouseLive.com/HouseList4/Default.aspx?userid=mc1

There is a list in highlighted place which is shown properly now.
31q.png
0
I'm looking for search application which uses solr search

one i found is Nutch but i am not very much attracted with the UI

Can you please let me know the applications which uses solar search for indexing local documents and peform search and navigate easily ?
0
Unable to install Angular on mac I got this error:
npm ERR! path /usr/local/bin/ng
npm ERR! code EEXIST
npm ERR! Refusing to delete /usr/local/bin/ng: ../lib/node_modules/angular-cli/bin/ng symlink target is not controlled by npm /usr/local/lib/node_modules/@angular/cli
npm ERR! File exists: /usr/local/bin/ng
npm ERR! Move it away, and try again.

npm ERR! A complete log of this run can be found in:
npm ERR!     /Users/saudalsahli/.npm/_logs/2018-09-02T09_31_09_443Z-debug.log
sauds-MacBook-Pro:~ saudalsahli$ sudo npm install -g @angular/cli
npm ERR! path /usr/local/bin/ng
npm ERR! code EEXIST
npm ERR! Refusing to delete /usr/local/bin/ng: ../lib/node_modules/angular-cli/bin/ng symlink target is not controlled by npm /usr/local/lib/node_modules/@angular/cli
npm ERR! File exists: /usr/local/bin/ng
npm ERR! Move it away, and try again.

npm ERR! A complete log of this run can be found in:
npm ERR!     /Users/saudalsahli/.npm/_logs/2018-09-02T09_33_27_509Z-debug.log
0
Does anyone know of resources either in books or on the web, or does anyone have experience of using SCSI Pass Through / Direct using (ideally VB6).
I am interested in how to set up the IOCTL_SCSI_PASS_THROUGH / DIRECT without using .net I have tried some sample .net code and it is clunky and very slow.
0
Hi all
We have a number of Android tablets, some of which are misbehaving. I need to be able to save (or send) the system logs (and maybe dmesg as well, if poss) continuously to the removeable SD card, or alternately, to send the logs out to an FTP server. Can someone help me do this please? I will not be able to "root" the devices.
Thanks in advance
Michael
0
PMI ACP® Project Management
LVL 12
PMI ACP® Project Management

Prepare for the PMI Agile Certified Practitioner (PMI-ACP)® exam, which formally recognizes your knowledge of agile principles and your skill with agile techniques.

Looking for link where all java related working applications are available or displayed or listed.

github has many projects however hard to find the working applications as many are sample ones and not updated to uptodate and no support if the project doesn't work.

example, https://en.wikipedia.org/wiki/Category:Software_programmed_in_Java_(programming_language)
0
How to support custom jsom share point online sites in mobile view. what are the options and customization available for rich mobile experience
0
Hi,
How to resolve 500 error on web page? I did deploy the web project properly but why did the following error comes out?
30v.png
0
Hi all,

I have problem to display my PDF file in an existing popup window using spring framework. The workflow is when I click a button from the main page, it popups a new window (child) and showing progress status. After the file finished generating, I set the view in controller and return to jsp. However, the PDF file displays (using DefaultResourceLoader and response.flushBuffer) in the main page instead of the popup window. I want to show in popup. Anything wrong? How can I specify which window the PDF should be displayed?

Please help. Thanks.
0
I would like to change the names of the members of the list. The list is of a CPI hierarchy - the trouble is the names are now ID numbers, that are difficult to interpret. Each one of the members has a readable tag, that is "CPI.Tag".

How would I swap the label that is used for the name  currently to the "CPI.Tag"? (the display of a few sample members is attached)
2018-08-14_13-32-00.png

I thought it would be something along the lines of names(jpCPIlist)<-jpCPIlist$CPI.Tag, but evidently not..
0
Generic Form, Controller, Service and Search fields for Java Web Application

I want to built an application where there will be 500 screens which needs basic CRUD operation and individual field search or combined search field option is required.

Everything when we build entity in Java/JPA we want to have separate controller, service, repository and search api.

Is any framework or open source it has all in common, where we can use the generic controller, service, repository and search and export options by default instead of writing any new code snippet

However we can extend whenever is required.

Please advise.
0

Programming Languages-Other

19K

Solutions

19K

Contributors

A programming language is a formal constructed language designed to communicate instructions to a machine, particularly a computer. Thousands of different programming languages have been created, mainly in the computer field, and many more still are being created every year. The description of a programming language is usually split into the two components of syntax (form) and semantics (meaning). Some languages are defined by a specification document (for example, the C programming language is specified by an ISO Standard), while other languages (such as Perl) have a dominant implementation that is treated as a reference. Some languages have both, with the basic language defined by a standard and extensions taken from the dominant implementation being common.