Java
/
I/O
- 1 Basics 9
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Classes S
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Objects S
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Arrays S
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Variables S
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Loops S
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Numbers S
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Strings S
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Exceptions S
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Regexp S
- 2 OOP 9
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Inheritance
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Polymorphism
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Static S
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Abstract
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Interfaces
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Constructors S
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Packages
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Nested Classes
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Final
- 3 Compiler 2
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Sublime Text S
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Apache Ant
- 4 Collections 8
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Lists
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Comparable S
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Sets
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Maps
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Generics
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Properties
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Streams
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Json
- 5 Threads 4
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Create Thread S
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Sleep
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Lock
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Scheduler
- 6 Design Patterns 4
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Singleton
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Observer
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Strategy
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Mediator
- 7 Swing 12
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Frame
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Panel
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Listener
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Combo Box
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Label
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Image
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Menu
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Table
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Layout
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Drawing
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Timer
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Designer
- 8 I/O 7
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Streams IO
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Socket
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Watching Files
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Mail
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Logger
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Clipboard
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Encrypt S
- 9 Effective 7
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Constructors S
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Dependency Injection
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Composition
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Interfaces Default
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Import Static S
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Enums
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Lambdas
- 10 Junit 5
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About Junit S
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Test Case
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Suite Test
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Annotations
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Exceptions
- 11 Lambdas 7
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Expressions S
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Functional Interfaces
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Streams
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Common Operations
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Default Methods
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Static Methods S
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Single Responsibility
- 12 JavaFX 6
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Openjfx
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Scene Builder
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First App
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Jar Archive
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On Action
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Change Listener
- 13 Maven 4
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Demo
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Spring Boot
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Junit
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Guava
- 14 Spring Boot 13
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Quick start S
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Rest service S
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Consuming rest S
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Templates S
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Security auth S
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Command line S
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Scheduled task S
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Ajax S
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Jdbc mysql S
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Encrypt password S
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Https S
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Jwt S
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Post request S
R
Q
Sreams I/O
FileWriter is used to save data to a text file.
copy
/**
* Write text to a file
*
* If the file does not exists it will be created
*/
import java.io.FileWriter;
import java.io.IOException;
class App {
public static void main(String[] args) throws IOException {
FileWriter writer = new FileWriter("Foo.txt");
writer.write("hello foo!");
writer.close();
}
}
Buffered input streams read data from a memory area known as buffer.
copy
/**
* Read text lines from a file
*
* Foo.txt contains 2 lines:
* Hello Foo
* Hello Foo 2
*/
import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;
class App {
public static void main(String[] args) throws IOException {
BufferedReader reader = new BufferedReader(
new FileReader("./Foo.txt")
);
String line;
while((line = reader.readLine()) != null) {
System.out.println(line);
// Hello Foo
// Hello Foo 2
}
reader.close();
}
}
Read a line of chars from console with an InputStream.
copy
import java.io.BufferedReader;
import java.io.InputStreamReader;
public class App {
public static void main(String[] args) throws Exception {
InputStreamReader stream = new InputStreamReader(System.in);
BufferedReader reader = new BufferedReader(stream);
a:while(true) {
String text = (String) reader.readLine();
switch(text) {
case "quit":
break a;
default:
System.out.println("User typed: " + text);
}
}
}
}
➥ Questions