Ragam Dan Fungsi Bahasa

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Mengatasi Kesalahan Crystal Report .NET

          Pernahkah mengalami problem program seperti gambar di bawah ini ?

dan biasanya ini terjadi jika kita mengeksekusi program dengan crystal report (saya menggunakan VS2010) disini saya ingin berbagi bagaimana cara menormalkan kembali :)

1. Pastikan target ftamework anda .NET framework 4 (ada di setting-> Compile->advanced compile Option)
2. coba perhatikan di Solution Explorer anda dan buka app.config
3. copy dan paste/replace barisan kode berikut :



<startup useLegacyV2RuntimeActivationPolicy="true">
    <supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.0"/>
  </startup>
4. restart visual studio anda dan jalankan kembali.

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Fungsi instanceof pada JAVA

             Di kesempatan kali ini saya ingin memberikan sedikit pengetahuan tentang penggunaan instanceof pada bahasa pemrograman JAVA. Sebelumnya sudah pernah belajar tentang Casting variabel pada JAVA bukan? sekarang kita akan memasuki sebuah masalah dalam beberapa blok program berikut:


public class Testinstanceof{
public static void main(String[]args){

Object siswa = new Student(); //implicit casting
//kemudian kita ingin memasukkan objek baru yang sama dengan class siswa contoh:

Student murid = siswa;

/*akan ada Compile error. pertanyaannya kenapa Object siswa = new Student bisa berjalan sedangkan Student murid = siswa  tidak ? itu karena objek Student adalah contoh dari objek tapi Objek bukan contoh dari student meskipun kita melihat bahwa murid adalah Objek Student, Compiler tidak terlalu pintar untuk mengetahui kalau murid adalah objek maka yang diperlukan sekarang adalah explicit Casting Contoh: */

Student murid = (Student)siswa;
}
}

kita bisa meng-cast contoh/instanceof dari sebuah subclass (kelas anak) atau dikenal dengan upcasting ke variabel Superclass(kelas induk), karena contoh/instanceof dari subclass selalu contoh dari kelas induknya. Ketika meng-cast/merubah contoh dari superclass ke variabel subclassnya (dikenal dengan downcasting), explicit casting harus digunakan untuk mengkonfirmasi maksud kita kepada kompiler dengan nama subclass (dengan notasi casting). agar casting bisa berhasil kita harus meyakinkan kompiler bahwa object yang di cast adalah contoh/instanceof subclass. kalau superclass bukan contoh dari subclass, runtime ClassCastException akan terjadi contohnya, kalau objek bukan contoh.instanceof Student (program yang tadi) maka si objek tadi tidak bisa di casting ke variabel student. sebuah praktek yang baik untuk meyakinkan sebuah variable adalah contoh/instanceof dari objek yang lain kita menggunakan instanceof operator. Perhatikan blok kode berikut:

...
Object siswa = new Student;
if (siswa instanceof Student){
System.out.println("Nama Siswa Adalah: " + siswa.getNama());
}
...

dari sini kita bisa tahu apakah variabel siswa adalah contoh/instanceof Student atau tidak. Dan dari sini juga semoga para pembaca bisa mengerti dan menyimpulkan apa fungsi dari instanceof pada bahasa pemrograman JAVA.

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ArrayList Pada JAVA

ArrayList pada Bahasa pemprograman JAVA


Array adalah sebuah variabel homogen yang bisa memuat lebih dari satu data cara membuatnya dalam java adalah  sebagai berikut :


public class Arr{

public static void main(string []args){

string[] siswa = new string[3]; //Jumlah String ada 3 buah (0,1,2)
siswa[0] = "Rifzky";
siswa[1] = "Avril Lavigne";
siswa[2] = "Camilla Belle"

// atau bisa juga seperti ini:
string Mahasiswa[] = {"Rifzky Alam", "Emma Watson", "Taylor Swift"};

// seperti ini juga boleh xD : string mahasiswa []; mahasiswa[0] = "hello"; ....dst

//print array

System.out.println(siswa[0] + Mahasiswa[1]);
}

}

namun pada kesempatan kali ini kita belajar Array list bukan array biasa, perbedaannya ArrayList memungkinkan para programmer untuk menulis data value dengan jumlah yang tidak tidak terbatas.

contoh membuatnya :

public class ArrList{

public static void main(String[]args){

java.util.ArrayList kota = new java.util.ArrayList();

kota.add("Bogor");
kota.add("Cianjur");
kota.add("Jakarta");
kota.add("Bandung");

//dst. untuk kali ini saya tulis 4 kota aja ya, mau tulis 100 pu gpp asal kuat hehe

System.out.println("Jumlah List? " + kota.size); //jumlah data dlm List
System.out.println("Apa Bogor dalam list? " + kota.contains("Bogor")) // cek isinya
System.out.println("Lokasi Bandung di nomor? " + kota.indexOf("Bandung")) //cari posisi kota Bandung

kota.remove("Jakarta"); //menghilangkan Jakarta dalam List Kota
}
}

Demikianlah cara kerja ArrayList pada bahasa pemprograman Java, Semoga Bermanfaat

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7 Tips Mudah Menjaga Kesehatan Ginjal

          Kesehatan menjadi harta yang tak ternilai harganya bagi kita. ini dapat kita rasakan diwaktu kondisi sakit. Sebab jika kita sakit akan menghabiskan waktu dan biaya yang tidak sedikit. Oleh karena itulah, kita harus tetap menjaga kesehatan tubuh kita utamanya organ ginjal.
Sahabat, tips kesehatan. Ginjal merupakan organ yang sangat vital pada tubuh kita. ini dikarenakan fungis ginjal sebagai organ yang berperan penting dalam mengatur keseimbangan asam-basa, pengaturan tekanan darah, merangsang sumsum tulang untuk membuat sel darah merah, membantu mempertahankan kalsium untuk tulang. Begitu besarnya peran ginjal bagi tubuh kita. Tips kesehatan kali ini akan membahas Cara Pintar Menjaga Kesehatan Ginjal :

1. Mengatur pola makan merupakan tips ampuh menjaga dan merawat kesehatan ginjal anda. Pilihlah makanan seperti buah-buahan, sayur-sayuran yang di tanam dengan tanpa pupuk kimia (organik) serta jauhilah makanan olahan, kurangi konsumsi garam berlebih, serta konsumsilah ikan atau daging putih tanpa lemak.

2. Menjaga pencernaan merupakan langkah yang dianjurkan untuk menjaga kesehatan ginjal anda. Ini dapat dilakukan dengan menambah konsumsi makanan probiotik dan prebiotik serta makanan yang memiliki atau kaya serat yang cukup tinggi.

3. Stop kebiasaan merokok merupakan langkah berikutnya yang sangat di anjurkan untuk menjaga kesehatan ginjal anda. ini dikarenakan, kandungan nikotin dalam rokok berperan penting dalam gangguan ginjal yang akan anda alami.

4. Stop dari minuman beralkohol sekarang juga. Ini di karenakan dengan mengkonsumsi alkohol akan berdampak buruk bagi kesehatan ginjal anda. karena mengakibatkan peningkatan tekanan darah dalam tubuh anda yang pada akhirnya berujung pada gangguan ginjal anda.

5. Minumlah air putih sesuai dengan kebutuhan tubuh kita. dalam hal ini 6-8 gelas sehari. Ini sangat baik untuk menjaga dan merawat kesehatan ginjal anda.

6. Rajin berolahraga merupakan tips paling mudah untuk menjaga kesehatan ginjal anda. dalam hal ini bisa dilakukan seperti jalan kaki atau berlari setiap pagi.

7. Usahakan tidak mengkonsumsi atau bahkan menghindari beberapa obat antibiotic dan anti nyeri. Ini dikarenakan dapat merusak ginjal anda atau konsultasikan tentang penggunaan obat tersebut kepada dokter spesialis terlebih dahulu.

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Pengenalan HTML.

     Jika anda pernah belajar komputer mengenai web pages pasti pernah mendengar, HTML adalah kepanjangan dari Hyper Text Markup Language, Hyper yang berarti banyak, Text berarti tulisan dan Markup Language berarti bahasa yang memakai notasi modern untuk mudah dibedakan (<> - </>), jadi HTML adalah bahasa yang memakai tulisan markup yang banyak. Oleh karenanya jika kita melihat script HTML banyak tulisan yg berawal dengan <bla-bla-bla> dan diakhiri dengan </bla-bla-bla> atau lebih dikenal dengan HTML Tag, Tag HTML digunakan untuk mendeskripsikan dokumen dari HTML itu sendiri seperti <title></title> merupakan deskripsi untuk judul HTML. HTML sering disebut dengan Web Pages atau lembaran Web.

     Dalam kesempatan ini saya ingin menjelaskan cara untuk membuat dokumen HTML sehingga bisa di tampilkan di browser internet seperti Mozilla Firefox, Google Chrome atau browser internet lainnya. ikuti langkah berikut ini

1. Buka Notepad anda atau jika ingin memakai applikasi khusus membuat HTML seperti sublime text, klik disini untuk download.
2. Tag pembuka HTML dengan menulis <html> (sebagai pengenal bahwa tulisan yg di buat adalah dalam format web page) kemudian tutup dengan tag </html>.
3. Buat kepala tulisan HTML dengan tag <head></head>
4. Diantara tag <head> </head> Buat tag untuk judul halaman HTML dengan tag <title> dan tulis judulnya terserah anda sebelum tag akhir </title>.
5. Setelah selesai dengan tag <head> kita buat tag <body> untuk isi halaman HTML nya.
6. Jika ingin membuat judul paragraf gunakan <h1> jangan lupa ditutup dengan </h1>
7. Ketik paragraf yang anda inginkan dengan <p> </p>.
8. Untuk membuat garis baru gunakan <br/>.
9. Simpan file (save as) dengan format .html contoh : latihan1.html

         Tampilannya akan kurang lebih seperti: 

Jika dibuka di browser akan terlihat seperti:

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The Usage Of interface in java

An interface is a collection of abstract methods. A class implements an interface, thereby inheriting the abstract methods of the interface.
An interface is not a class. Writing an interface is similar to writing a class, but they are two different concepts. A class describes the attributes and behaviors of an object. An interface contains behaviors that a class implements.
Unless the class that implements the interface is abstract, all the methods of the interface need to be defined in the class.
An interface is similar to a class in the following ways:

• An interface can contain any number of methods.
• An interface is written in a file with a .java extension, with the name of the interface matching the name of the file.
• The bytecode of an interface appears in a .class file.
• Interfaces appear in packages, and their corresponding bytecode file must be in a directory structure that matches the package name.

However, an interface is different from a class in several ways, including:

• You cannot instantiate an interface.
• An interface does not contain any constructors.
• All of the methods in an interface are abstract.
• An interface cannot contain instance fields. The only fields that can appear in an interface must be declared both static and final.
• An interface is not extended by a class; it is implemented by a class.
• An interface can extend multiple interfaces.

Declaring Interfaces:

The interface keyword is used to declare an interface. Here is a simple example to declare an interface:

Example:

Let us look at an example that depicts encapsulation:

/* File name : NameOfInterface.java */
import java.lang.*;
//Any number of import statements

public interface NameOfInterface
{
   //Any number of final, static fields
   //Any number of abstract method declarations\
}

Interfaces have the following properties:

• An interface is implicitly abstract. You do not need to use the abstract keyword when declaring an interface.
• Each method in an interface is also implicitly abstract, so the abstract keyword is not needed.
• Methods in an interface are implicitly public.

Example:

/* File name : Animal.java */
interface Animal {

   public void eat();
   public void travel();
}

Implementing Interfaces:

When a class implements an interface, you can think of the class as signing a contract, agreeing to perform the specific behaviors of the interface. If a class does not perform all the behaviors of the interface, the class must declare itself as abstract.
A class uses the implements keyword to implement an interface. The implements keyword appears in the class declaration following the extends portion of the declaration.

/* File name : MammalInt.java */
public class MammalInt implements Animal{

   public void eat(){
      System.out.println("Mammal eats");
   }

   public void travel(){
      System.out.println("Mammal travels");
   } 

   public int noOfLegs(){
      return 0;
   }

   public static void main(String args[]){
      MammalInt m = new MammalInt();
      m.eat();
      m.travel();
   }
} 

This would produce the following result:

Mammal eats
Mammal travels

When overriding methods defined in interfaces there are several rules to be followed:

• Checked exceptions should not be declared on implementation methods other than the ones declared by the interface method or subclasses of those declared by the interface method.
• The signature of the interface method and the same return type or subtype should be maintained when overriding the methods.
• An implementation class itself can be abstract and if so interface methods need not be implemented.

When implementation interfaces there are several rules:

• A class can implement more than one interface at a time.
• A class can extend only one class, but implement many interfaces.
• An interface can extend another interface, similarly to the way that a class can extend another class.

Extending Interfaces:

An interface can extend another interface, similarly to the way that a class can extend another class. The extends keyword is used to extend an interface, and the child interface inherits the methods of the parent interface.
The following Sports interface is extended by Hockey and Football interfaces.

//Filename: Sports.java
public interface Sports
{
   public void setHomeTeam(String name);
   public void setVisitingTeam(String name);
}

//Filename: Football.java
public interface Football extends Sports
{
   public void homeTeamScored(int points);
   public void visitingTeamScored(int points);
   public void endOfQuarter(int quarter);
}

//Filename: Hockey.java
public interface Hockey extends Sports
{
   public void homeGoalScored();
   public void visitingGoalScored();
   public void endOfPeriod(int period);
   public void overtimePeriod(int ot);
}

The Hockey interface has four methods, but it inherits two from Sports; thus, a class that implements Hockey needs to implement all six methods. Similarly, a class that implements Football needs to define the three methods from Football and the two methods from Sports.

Extending Multiple Interfaces:

A Java class can only extend one parent class. Multiple inheritance is not allowed. Interfaces are not classes, however, and an interface can extend more than one parent interface.
The extends keyword is used once, and the parent interfaces are declared in a comma-separated list.
For example, if the Hockey interface extended both Sports and Event, it would be declared as:

public interface Hockey extends Sports, Event

Tagging Interfaces:

The most common use of extending interfaces occurs when the parent interface does not contain any methods. For example, the MouseListener interface in the java.awt.event package extended java.util.EventListener, which is defined as:

package java.util;
public interface EventListener
{}

An interface with no methods in it is referred to as a tagging interface. There are two basic design purposes of tagging interfaces:
Creates a common parent: As with the EventListener interface, which is extended by dozens of other interfaces in the Java API, you can use a tagging interface to create a common parent among a group of interfaces. For example, when an interface extends EventListener, the JVM knows that this particular interface is going to be used in an event delegation scenario.
Adds a data type to a class: This situation is where the term tagging comes from. A class that implements a tagging interface does not need to define any methods (since the interface does not have any), but the class becomes an interface type through polymorphism.

source : http://www.tutorialspoint.com

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What is a Log File?

                    A log file is a recording of everything that goes in and out of a particular server. It is a concept much like the black box of an airplane that records everything going on with the plane in the event of a problem. The information is frequently recorded chronologically, and is located in the root directory, or occasionally in a secondary folder, depending on how it is set up with the server. The only person who has regular access to the log files of a server is the server administrator, and a log file is generally password protected, so that the server administrator has a record of everyone and everything that wants to look at the log files for a specific server.
                   Servers are not the only system that use log files. Process control systems, as well as computer operating systems have logging subsystems that work exactly like a log file does. While these are more sophisticated than a simple log file, most times it is the same concept, where a log message is recorded in the file and saved until it is needed. Other forms of log filing use more sophisticated systems, some of which even analyze the logs before they are needed, but it all depends on where the log file is located.
The point of a log file is to keep track of what is happening with the server. If something should malfunction within a complex system, there may be no other way of identifying the problem. Log files are also used to keep track of complex systems, so that when a problem does occur, it is easy to pinpoint and fix. Log files are also important to keeping track of applications that have little to no human interaction, such as server applications. There are times when log files are too difficult to read or make sense of, and it is then that log file analysis is necessary. Log file analysis is generally performed by some kind of computer program that makes the log file information more concise and readable format. Log files can also be used to correlate data between servers, and find common problems between different systems that might need one major solution to repair them all.

and more about log file i got from http://computer.howstuffworks.com/
is

Log Files

Your computer is full of log files that provide evidence of what you've been doing. Through these log files, a system administrator can determine what Web sites you've accessed, whom you are sending e-mails to and receiving e-mails from and what applications are being used. So, if you are downloading MP3 files, there's more than likely a log file that holds data about that activity.
In many cases, this information can be located even after you've deleted what you thought was all the evidence -- but deleting an e-mail, or a file, doesn't erase the trail. Here are a few places where log files can be found:

• Operating systems
• Web browsers (in the form of a cache)
• Applications (in the form of backups)
• E-mail

If the hard drives of an employee's computer and a system administrator's computer are connected, a system administrator can view the log files remotely. The administrator has to have access to the drive to check files remotely. Otherwise, a system administrator can check the computer before an employee comes in or after the employee leaves for the day.

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File Extension for Ms.SQL SERVER DATABASE

I was reading an article over the weekend where the author pointed out that the standard naming convention for SQL Server database files was .MDF for the data file, LDF for the log file and NDF for additional data files.  This was good stuff so far, then the author stated that these can be changed if you want to mess around with your other DBA’s.  I have known for years that the file extensions are merely suggestions (best practice) and that you could change them if you so chose.  Some companies may have policies defined that data files must have an extension of .001 and logs .002, etc.

What I wish the author had pointed out was that if you deviate from what is standard for file extension naming for your data and log files, please make sure your security department adds those new extensions to the list of excludes for your virus protection.  If not, you will have successfully launched a denial of service (DOS) attack against yourself.

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