![Pembahasan Program
0: // Exercise 1: HelloMe.java
1: // NIK: 730015, NAMA: Niko Ibrahim
2: public class HelloMe {
3: public static void main (String args[ ]) {
4: System.out.println("Hello World, Niko!");
5: }
6: }
Line 0: Komentar program, judul program, keterangan penting.
Line 1: Selalu tuliskan identitas penulis program.
Line 2: - Nama kelas. Setiap program Java minimal memiliki 1 deklarasi kelas.
- Kelas diawali huruf kapital untuk setiap kata.
- Untuk men-save public class ke file, harus diberi nama sesuai dengan
nama kelas
tsb dan diakhiri dengan ekstensi .java. Tentang public akan dibahas
nanti.
Line 3: main method the starting point of every Java application
Line 4: instruksi pada komputer untuk menulis suatu String (kata-kata)](https://image.slidesharecdn.com/212kuliah01-pengenalanpemrogramanberorientasiobjekjava-130717031041-phpapp01/85/212-kuliah-01-pengenalan-pemrograman-berorientasi-objek-java-18-320.jpg)
![Latihan 2: Operasi Penambahan Integer
// Addition program that displays the sum of two numbers.
import java.util.Scanner; // program uses class Scanner
public class Addition
{
// main method begins execution of Java application
public static void main( String args[] )
{
// create Scanner to obtain input from command window
Scanner input = new Scanner( System.in );
int number1; // first number to add
int number2; // second number to add
int sum; // sum of number1 and number2
System.out.print( "Enter first integer: " ); // prompt
number1 = input.nextInt(); // read first number from user
System.out.print( "Enter second integer: " ); // prompt
number2 = input.nextInt(); // read second number from user
sum = number1 + number2; // add numbers
System.out.print( "Sum is " + sum ); // display sum
} // end method main
} // end class Addition](https://image.slidesharecdn.com/212kuliah01-pengenalanpemrogramanberorientasiobjekjava-130717031041-phpapp01/85/212-kuliah-01-pengenalan-pemrograman-berorientasi-objek-java-33-320.jpg)
![Latihan 3: InvoiceApp.java
// Latihan 3: InvoiceApp.java
import java.util.Scanner;
public class InvoiceApp {
public static void main (String args[]) {
// create a Scanner object
Scanner sc = new Scanner(System.in);
// read a string
System.out.print("Enter product code: ");
String productCode = sc.next();
// read a double value
System.out.print("Enter price: ");
double price = sc.nextDouble();
// read an int value
System.out.print("Enter quantity: ");
int quantity = sc.nextInt();
// perform a calculation and display the result
double total = price * quantity;
System.out.println();
System.out.println(quantity + " " + productCode + " @ "
+ price + " = " + total);
}
}](https://image.slidesharecdn.com/212kuliah01-pengenalanpemrogramanberorientasiobjekjava-130717031041-phpapp01/85/212-kuliah-01-pengenalan-pemrograman-berorientasi-objek-java-36-320.jpg)
212 kuliah 01 pengenalan pemrograman berorientasi objek (java)
- 1. IF307 – PEM ROGRAM AN B ERORIENTASI OB JEK (JAVA) N I K O I B R A H I M , M I T E R I C K C O S T A N I O , S . K O M F A K U L T A S T E K N O L O G I I N F O R M A S I U N I V E R S I T A S K R I S T E N M A R A N A T H A © 2 0 1 0 Kuliah 01 Pengenalan PBO Berbasis Java
- 2. Class Attendance Lectures schedule: Class A: Monday, 08.00 – 10.00 Class B: Monday, 10.30 – 13.00 Practical work schedule: Class A: Wednesday, 08.00 – 10.00 Class B: Wednesday, 10:00 – 12:00 All students must meet 75% of lecture‟s attendances to be eligible for the exams.
- 3. On Time Students are expected to come on time for both lectures and practicals sessions. More than 10 minutes means „no proof of attendace‟
- 4. Books & References You may use any books you like most However, for your guidelines: Object of Java (BlueJ Edition) Core Java 2 Volume 1 Fundamental 8th Edition Other References Java 6 API Documentation (Java Doc) BlueJ Tutorials BlueJ Reference Manual
- 5. Practical Works There are several practical works Checkpoint system (1-5 stage for each pracs) Checkpoint 1 - basic concepts (everyone) Checkpoint 2 - understand and describe (nearly everyone) Checkpoint 3 - apply to new contexts (most) Checkpoint 4 - compare, synthesize (only top 40%) Checkpoint 5 - generalize, hypothesize, analyze (only top 20%) Try your best, do not copy other‟s work No late submission, no excuse No cheating, no copying, no sharing Work independently, ask for help
- 6. Softwares and Tools JDK 1.6 + Java API Documentation Editors: BlueJ (www.bluej.org): java editor + OOP concept JGrasp (www.jgrasp.org): Java editor NetBeans 6.9 (Java IDE) Others: Text Editor: Notepad, EditPlus, TextPad, UltraEdit, dll Java Editor: JCreator, DrJava IDE: Eclipse, IntelliJ IDEA
- 7. Silabus Perkuliahan Pertemuan Perkuliahan Praktikum Materi Tanggal Minggu 1 Perkuliahan ditiadakan 09 Agt - Minggu 2 Pengenalan Pemrograman Berorientasi Objek (Java) 16 Agt P1 – Java Lang 1 Minggu 3 Mengenal lebih dalam Java API dan Java Documentation 23 Agt P2 – Java Lang 2 Minggu 4 Konsep Pemrograman Berorientasi Objek: Class, Object 30 Agt P3 – Java Sun Rise Minggu 5 Method, Attributes, Encapsulation, & Overloading 06 Sep P4 – Smiley Face Minggu 6 Libur Hari Raya Idul Fitri 13 Sep P5 – Java Clock Minggu 7 Konsep Inheritance, Overriding, & Polymorphism 20 Sep P6 – Color Matcher Minggu 8 Review Materi 27 Sep Ujian Praktikum UTS Ujian Teori 4-6 Okt - Minggu 9 Abstract Class dan Interface 18 Okt P7 Minggu 10 OOP Advanced Features & Exception Handling 25 Okt P8 Minggu 11 Java Collections Framework 01 Nov P9 Minggu 12 Java Graphical User Interface (GUI) Bagian 1 08 Nov P10 Minggu 13 Java Graphical User Interface (GUI) Bagian 2 15 Nov P11 Minggu 14 Java Input/Output (Java IO) 22 Nov P12 Minggu 15 Review Materi 29 Nov Ujian Praktikum UAS Ujian Teori 6-18 Des -
- 8. What Java? 1991: project “Oak” by James Gosling Berorientasi objek, berdasarkan bahasa C++ Dirancang untuk memprogram “home applicances” seperti TV sets, freezers, dll Perlu berjalan di berbagai platform/processor dan harus murah 1994: HotJava (browser yang mampu menjalankan aplikasi java) 1995: implementasi publik yang pertama kali Semua browsers dapat menjalankan aplikasi java di web (java applet) 1998: The advent of Java 2: J2EE, J2ME, & J2SE 2002: Microsoft memperkenalkan bahasa baru yang memiliki sintaks yang mirip Java yaitu C# sebagai bagian dari platform .NET, sekaligus menghilangkan Java dari Windows (harus install manual) 2006: Sun released parts of Java as Free/Open Source Software! Versi saat ini: Java Development Kit (JDK) versi 1.6, biasa disebut JDK 6 In 2009, Sun Microsystem (the creator of Java) was acquired by Oracle (2nd largest software company in the world)
- 9. Why Java? cheap – almost all tools/softwares/components are available for free! simple - partially modeled on C & C++ but greatly simplified and improved (eliminates pointers, simplifies multiple inheritance, etc.) object-oriented programming language any conceptual component in your problem can be represented as an object in your program portable Java programs are compiled (translated) into the Java Virtual Machine (JVM) code called bytecode bytecode is machine-independent and run on any machine with a Java interpreter the Java interpreter (part of JVM) further translates the bytecode into the machine language of the target machine once compiled programs can run on any platform (with JVM installed) without being recompiled
- 10. Why Java? (cont.) robust (reliable) - well developed exception handling mechanisms, early checking for errors, etc. secure - several built-in security mechanisms multithreaded - can perform several tasks simultaneously
- 11. Where Java? Desktop applications Web applications Ebay, Amazon, AirAsia, klikBCA Mobile Devices: mobile phone, smartphone, Blackberry, PDA Smart Card: Simcard, Credit Card, RFID Card (Contoh: E-Tol) Enterprise Applications SAP, JD Edward, PeopleSoft, Oracle Business Suite All machines & OS: windows, linux, mac, solaris
- 12. Java Platform http://download.oracle.com/javase/6/docs/ The following conceptual diagram illustrates all the component technologies in Java SE platform and how they fit together.
- 13. Typical Java Development Environment Ada 5 tahapan pengembangan aplikasi menggunakan Java: Tahap 1: Creating a program Tahap 2: Compiling the program into bytecodes Tahap 3: Loading the program into memory Tahap 4: Byte verification Tahap 5: Execution
- 14. Tahap 1: Creating a program Pada tahap ini, kita membutuhkan suatu editor untuk menulis kode program. Kode program disimpan pada file berekstensi “.java” Editor yang dapat digunakan: Editor teks sederhana: notepad, editPlus, Textpad, UltraEdit Editor teks berbasis Java: JGrasp, JCreator, DoctorJava Editor teks + diagram sederhana: BlueJ Integrated Development Environment (IDE): Free: NetBeans, Eclipse, Oracle JDeveloper Commercial: IntelliJ IDEA, IBM, BEA, Borland JBuilder
- 15. Tahap 2: Compiling Pada tahap ini, kita compile kode program menjadi bytecodes dengan menggunakan perintah “javac” Contoh: Kita membuat program dengan nama “Welcome.java” Perintah compile: javac Welcome.java Apabila proses compile berhasil, maka compiler akan menghasilkan sebuah file dengan ekstensi “.class” yaitu “Welcome.class” File “.class” bukan bahasa mesin, melainkan merupakan Bytecodes yang dapat dimengerti oleh Java Virtual Machine (JVM) JVM inilah yang akan mengeksekusi bytecodes ke dalam bahasa mesin JVM inilah yang menyebabkan Java begitu powerful, secure, scalable dan multi-platform/portable Bytecode ini dapat dieksekusi di mesin/platform apapun asalkan telah diinstal JVM yang dapat mengerti versi Java tempat bytecode tersebut dicompile sebelumnya Untuk menjalankan JVM dan mengeksekusi program, kita gunakan perintah “java” Misalnya: java Welcome
- 16. Tahap 3-5 Phase 3: Loading a Program into Memory In Phase 3, the program must be placed in memory before it can execute a process known as loading. The class loader takes the .class files containing the program's bytecodes and transfers them to primary memory. The class loader also loads any of the .class files provided by Java that our program uses. Phase 4: Bytecode Verification In Phase 4, as the classes are loaded, the bytecode verifier examines their bytecodes to ensure that they are valid and do not violate Java's security restrictions. Phase 5: Execution In Phase 5, the JVM executes the program's bytecodes, thus performing the actions specified by the program.
- 17. Latihan 1: HelloMe.java Berdasarkan program “HelloWorld.java”, buatlah sebuah program baru bernama HelloMe.java Pada saat di-run, program harus menampilkan pesan sbb: Hello World, Niko! Note: Ganti dengan nama Anda sendiri… Biasakan beri NRP dan Nama anda (dalam bentuk comment) Pertanyaan: apa perbedaan antara print dan println ?
- 18. Pembahasan Program 0: // Exercise 1: HelloMe.java 1: // NIK: 730015, NAMA: Niko Ibrahim 2: public class HelloMe { 3: public static void main (String args[ ]) { 4: System.out.println("Hello World, Niko!"); 5: } 6: } Line 0: Komentar program, judul program, keterangan penting. Line 1: Selalu tuliskan identitas penulis program. Line 2: - Nama kelas. Setiap program Java minimal memiliki 1 deklarasi kelas. - Kelas diawali huruf kapital untuk setiap kata. - Untuk men-save public class ke file, harus diberi nama sesuai dengan nama kelas tsb dan diakhiri dengan ekstensi .java. Tentang public akan dibahas nanti. Line 3: main method the starting point of every Java application Line 4: instruksi pada komputer untuk menulis suatu String (kata-kata)
- 19. Compile & Run menggunakan command window Kita dapat menggunakan command window untuk melakukan compile dan run program Java. Jalankan command window: Start menu run ketik cmd Masuk ke direktori tempat Anda menyimpan file HelloMe.java PERINTAH COMPILE : javac HelloMe.java PERINTAH RUN : java HelloMe Note: JAVA PATH harus di-set terlebih dahulu di sistem operasi
- 20. print, println,dan printf Untuk menuliskan sesuatu, Java memberikan 3 pilihan methods: print posisi akhir kursor berada di garis yang sama Contoh: System.out.print ("Hello World"); println posisi akhir kursor berada di garis yang baru (seolah menekan enter) Contoh: System.out.println("Hello World"); printf print dalam bentuk format tertentu (f = formatted) Contoh: System.out.printf("%sn %sn", "Hello", "World");
- 21. Karakter Khusus Kita juga dapat memasukan karakter khusus ke dalam String. Untuk itu kita perlu menggunakan tanda “escape”, sbb: Contoh: Sequence Character n New line t Tab r Return ” Quotation Mark Backslash String Result "Code: JSPSnPrice: $50.25" Code: JSPS Price: $50.25 "NikotIbrahimrMaranathatUniversity" Niko Ibrahim Maranatha University "Type "x" to exit" Type "x" to exit "C:javafiles" C:javafiles
- 22. Tipe Data Primitif Java memiliki 8 tipe data primitif Type Bits Bytes Minimum Range Maximum Range byte 8 1 -128 or -27 127 or 27-1 short 16 2 -32,768 or -215 32,767 or 215-1 int 32 4 -2,147,483,648 or -231 2,147,483,647 or 231-1 long 64 8 -263 263-1 float 32 4 -3.4E38 3.4E38 double 64 8 -1.7E308 1.7E308 char 16 2 n/a n/a boolean 8 1 n/a n/a float 7 significant digits double 16 significant digits
- 23. Variabel & Assignment Java merupakan bahasa pemrograman yang bersifat static, artinya kita harus mendeklarasikan nama variabel sebelum meng-assign suatu nilai Sintaks: tipeData namaVariabel Contoh: int counter; counter = 1; Kita juga dapat secara langsung meng-assign suatu nilai kepada variabel: int counter = 1; boolean valid = false; char letter = ‘A’; char letter = 65; double distance = 3.65e+9; Untuk menginisialisai suatu konstanta, kita gunakan keyword “final”: final int DAYS_IN_NOVEMBER = 30; final double SALEX_TAX = 0.75
- 24. String di Java String dapat berisi huruf, angka, dan karakter khusus String bukan merupakan tipe data primitif melainkan tipe data reference Untuk menyambung (concat) dua/lebih string, gunakan operator + Syntax: String variableName = value; Examples: String message1 = "Invalid data entry"; String message2 = " "; String message3 = null; String firstName = "Niko"; String lastName = "Ibrahim"; String name = firstName + " " + lastName;
- 25. Operator Aritmatika Program seringkali membutuhkan berbagai operasi aritmatika. Java menyediakan berbagai operasi aritmatika untuk melakukan: Penjumlahan, Pengurangan, Pembagian, Perkalian, Sisa Pembagian
- 26. Parentheses ( ) Kita dapat menggunakan tanda kurung dalam melakukan operasi aritmatika. Contoh: a dikalikan dengan hasil penjumlahan antara b dengan c Yang manakah yang benar? 1) a * b + c 2) a * (b + c) 3) (a * (b + c)) Note: operasi di dalam kurung akan diproses pertama kali!
- 27. Precedence dari operator aritmatika Berikut ini adalah urutan pengerjaan operasi aritmatika (precedence) Contoh urutan pengerjaan:
- 28. More: Operator Aritmatika Operator Name # Operands Description + Addition 2 Add two operands - Subtraction 2 Subtract the right operand from the left * Multiplication 2 Multiplies the right operand and left operand / Division 2 Divides the right operand into the left operand % Modulus 2 Returns the value that is left over after dividing the right operand into the left operand ++ Increment 1 Adds 1 to the operand (x = x + 1) -- Decrement 1 Subtracts 1 from the operand (x = x -1) + Positive Sign 1 Promotes byte, short, and char types to the int type - Negative Sign 1 Changes a positive value to negative, and vice versa Secara keseluruhan Java memiliki 9 operator aritmatika:
- 29. Contoh-contoh operasi aritmatika Integer Arithmetic: int x = 14; int y = 8; Double Arithmetic: double a = 8.5; double b = 3.4; Operations Results Operations Results int result1 = x + y; int result2 = x – y; int result3 = x * y; int result4 = x / y; int result5 = x % y; int result6 = -y + x; int result7 = --y; int result8 = ++x; result1 = 22 result2 = 6 result3 = 112 result4 = 1 result5 = 6 result6 = 6 result7 = 7 result8 = 15, x = 15 double result9 = a + b; double result10 = a – b; double result11 = a * b; double result12 = a / b; double result13 = a % b; double result14 = -a + b; double result15 = --a; double result16 = ++b; result9 = 11.9 result10 = 5.1 result11 = 28.90 result12 = 2.5 result13 = 1.7 result14 = -5.1 result15 = 7.5 result16 = 4.4 Character Arithmetic: char letter1 = ‘C’; // letter1 = ‘C’ Unicode integer is 67 char letter2 = ++letter1; // letter2 = ‘D’ Unicode integer is 68
- 30. Shorcut Assignment Operators Java memiliki 6 shortcut assignment operators: Operator Name Description = Assignment Assigns a new value to the variable += Addition Adds the operand to the starting variable value of the variable and assigns the result to the variable -= Subtraction Subtracts the operand from the starting value of the variable and assigns the result to the variable *= Multiplication Multiplies the operand by the starting value of the variable and assigns the result to the variable /= Division Divides the operand by the starting value of the variable and assigns the result to the variable %= Modulus Derives the value that is left over after dividing the right operand by the value in the variable, and then assigns this value to the variable
- 31. Contoh shortcut assignment operator count += 1; // count is increased by 1 count -= 1; // count is decreased by 1 total += 100.0; // total is increased by 100.0 total -= 100.0; // total is decreased by 100.0 price *= .8; // price is multiplied by 0.8 sum += nextNumber;// sum is increased by the value of nextNumber
- 32. Using Console for Input & Output Mulai Java versi 5, cara paling mudah untuk mendapatkan input dari console adalah dengan menggunakan Scanner class Untuk menampilkan output ke console adalah menggunakan method (fungsi) System.out.println Sebelum menggunakan Scanner class, kita harus melakukan proses import sbb: import java.util.Scanner; Untuk membaca input dari console, kita buat objek scanner dengan cara menuliskannya sbb: Scanner sc = new Scanner(System.in); Ada 4 buah methods dari objek Scanner (yaitu sc) yang dapat kita gunakan sesuai kebutuhan: Method Description next() or nextLine() Reads a String value from the user nextInt() Reads an integer value from the user nextDouble() Reads a double value from the user nextBoolean() Reads a boolean value from the user
- 33. Latihan 2: Operasi Penambahan Integer // Addition program that displays the sum of two numbers. import java.util.Scanner; // program uses class Scanner public class Addition { // main method begins execution of Java application public static void main( String args[] ) { // create Scanner to obtain input from command window Scanner input = new Scanner( System.in ); int number1; // first number to add int number2; // second number to add int sum; // sum of number1 and number2 System.out.print( "Enter first integer: " ); // prompt number1 = input.nextInt(); // read first number from user System.out.print( "Enter second integer: " ); // prompt number2 = input.nextInt(); // read second number from user sum = number1 + number2; // add numbers System.out.print( "Sum is " + sum ); // display sum } // end method main } // end class Addition
- 34. Variabel dan Konsep Memori Nama variable seperti number1, number2, dan sum sebenarnya berkorenpondensi dengan lokasi di memori komputer. Setiap variabel memiliki nama, tipe, ukuran, dan nilai Kode dari contoh 2: number1 = input.nextInt(); // read first number from user Pada saat kode tsb dieksekusi, nomor yang diketik oleh user akan disimpan ke suatu lokasi dimemori yang telah diberikan kepada number1 oleh compiler. Misal, user memasukkan angka 45, maka komputer akan menyimpan nilai integer ke lokasi number1 sbb:
- 35. Variabel dan Konsep Memori (cont.) number2 = input.nextInt(); // read second number from user Memory locations after storing values for number1 and number2. sum = number1 + number2; // add numbers Memory locations after calculating and storing the sum of number1 and number2.
- 36. Latihan 3: InvoiceApp.java // Latihan 3: InvoiceApp.java import java.util.Scanner; public class InvoiceApp { public static void main (String args[]) { // create a Scanner object Scanner sc = new Scanner(System.in); // read a string System.out.print("Enter product code: "); String productCode = sc.next(); // read a double value System.out.print("Enter price: "); double price = sc.nextDouble(); // read an int value System.out.print("Enter quantity: "); int quantity = sc.nextInt(); // perform a calculation and display the result double total = price * quantity; System.out.println(); System.out.println(quantity + " " + productCode + " @ " + price + " = " + total); } }
- 37. Ekspresi Boolean Ekpresi Boolean biasanya digunakan untuk mengatur control statements. Ekpresi Boolean menghasilkan nilai true atau false. Ada 6 operator relational yang membandingkan operand bertipe data primitif dan menghasilkan nilai boolean. Dalam suatu ekpresi boolean, suatu operand dapat berupa literal, ekpresi aritmatika, maupun keyword true atau false. Operator Name Description == Equality Returns a true value if both operands are equals != Inequality Returns a true value if the left and right operands are not equal > Greater Than Returns a true value if the left operand is greater than the right operand < Less Than Return a true value if the left operand is less than the right operand >= Greater Than Or Equal Returns a true value if the left operand is greater than or equal to the right operand <= Less Than or Equal Return a true value if the left operand is less than or equal to the right operand
- 38. Contoh ekpresi boolean discountPercent == 2.3 // equal to a numeric literal letter == ‘y’ // equal to a char literal isValid == false // equal to the false value subtotal != 0 // not equal to a numeric literal years > 0 // greater than a numeric literal i < months // less than a variable subtotal >= 500 // greater than or equal to a numeric literal quantity <= reorderPoint // less than or equal to a variable Kita juga dapat menggabungkan beberapa nilai Boolean dengan menggunakan operator AND dan OR: Operator Name Example Description && AND a && b true if both a and b are true || OR a || b true if either a or b (or both) is true ^ XOR a ^ b true if only a or b is true ! NOT !a true if a is not true
- 39. String Comparison Karena String adalah suatu objek, bukan tipe data primitif, kita tidak dapat menggunakan operator relational untuk membandingkannya. Kita harus menggunakan method “equals” atau “equalgnoreCase” yang dimiliki oleh kelas String. Contoh: firstName.equals("Niko"); // equal to a string literal firstName.equalsIgnoreCase("Niko"); // equal to a string literal firstName.equals(""); // equal to an empty string !lastName.equals("Ibrahim"); // not equal to a string literal !code.equalsIgnoreCase(productCode); // not equal to another string variable firstName == null // equal to a null value firstName != null // not equal to a null value Java 6 only: firstName.isEmpty() // check if firstName is an empty string
- 40. Next Week! Struktur Control: Looping For Loop For Each Loop While Loop Do While Loop Branching If Else Switch Case Konsep Arrays Java Documentation