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→Exceptions
===With apt===
===With apt===
<nowiki>sudo apt-add-repository ppa:webupd8team/java
<nowiki>sudo apt-add-repository ppa:webupd8team/java
sudo apt-get update
sudo apt-get install oracle-java8-installer</nowiki>
Also ensure your JAVA_HOME variable has been set to:
Also ensure your JAVA_HOME variable has been set to:
System.out.println("My integer is: " + myInt);
System.out.println("My integer is: " + myInt);
}
}
}</source>
}</source><syntaxhighlight lang="java">
//Java 11
" ".isBlank(); // --> true
" lr ".strip(); //Java 11
" lr ".stripLeading().replace(" ", "@");
" lr ".stripTrailing().replace(" ", "@");
"line1\nline2\nline3".lines().forEach(System.out::println);
//Java 12
"UPPER".transform(s -> s.substring(2));
//Java 13
"My name is %s. My age is %d".formatted("Rafa", 40);
//Java 14
</syntaxhighlight>
==Enum type==
==Enum type==
See code example:<br />
See code example:<br />
words.contains("Dog");
words.contains("Dog");
words.indexOf("Cat");
words.indexOf("Cat");
</syntaxhighlight>
</syntaxhighlight>List.of() and List.copyOf() creates unmodifiable lists copyOf is introduced on Java 10
===ArrayList===
===ArrayList===
List<String> list = List.of("Apfel", "Junge", "Hund");
List<String> list = List.of("Apfel", "Junge", "Hund");
Files.write(filePath, list);
Files.write(filePath, list);
}
}
</syntaxhighlight>
===readString writeString (Java 11)===
<syntaxhighlight lang="java">
import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
public class FileReadWriteRunner {
public static void main(String[] args) throws IOException {
// Read
Path path = Paths.get("./file.txt");
String fileContent = Files.readString(path);
System.out.println(fileContent);
// Write
String newFileContent = fileContent.replace("Line", "Lines");
Path path = Paths.get("./newfile.txt");
Files.writeString(newFilePath, newFileContent);
}
}
}
}
==Exceptions==
==Exceptions==
[http://docs.oracle.com/javase/8/docs/api/java/lang/Exception.html Class Exception]
[http://docs.oracle.com/javase/8/docs/api/java/lang/Exception.html Class Exception]
[https://github.com/in28minutes/in28minutes-initiatives/blob/master/The-in28Minutes-TroubleshootingGuide-And-FAQ/quick-start.md Exception Troubleshooting]
===trows===
===trows===
<source lang="java">
<source lang="java">
System.out.print(Season.SPRING.getValue());
System.out.print(Season.SPRING.getValue());
System.out.print(Arrays.toString(Season.values()));
System.out.print(Arrays.toString(Season.values()));
}
}
</syntaxhighlight>
====module-info.java====
requires: allows usage of other modules
requires transitive: allows usage of other modules and modules that use this module will also have access to it
exports: allows other packages to use your classes
<br />
==Predicate Not==
Java 11<syntaxhighlight lang="java">
import java.util.List;
import java.util.function.Predicate;
public class PredicateNotRunner {
public static boolean isEven(Integer number){
return number&2==0;
}
public static void main(String[] args){
List<Integer> numbers = List.of(3, 4, 5, 57, 65, 88);
// Predicate<Integer> evenNumberPredicate = number -> number%2==0;
// numbers.stream().filter(evenNumberPredicate).forEach(System.out::println);
numbers.stream().filter(Predicate.not(PredicateNotRunner::isEven)).forEach(System.out::println);
}
}
}
}
</syntaxhighlight>
</syntaxhighlight>
== Logger ==
==Logger==
<syntaxhighlight lang="java">
<syntaxhighlight lang="java">
import java.util.logging.Logger
import java.util.logging.Logger
Hibernate → Java ORM framework for web design
Hibernate → Java ORM framework for web design
== java cli ==
==java cli==
<syntaxhighlight lang="bash">
<syntaxhighlight lang="bash">
# Compile class
# Compile class
# Run java application
# Run java application
java someclass.jar
java -jar someclass.jar
# List module dependencies
# List module dependencies
</syntaxhighlight>
</syntaxhighlight>
==Frameworks==
[[Java: Spring|Spring]]
==Java and Eclipse troubleshooting==
====Default Home Folder for JDK====
*Windows: C:\Program Files\Java\jdk-{version}
**Example for JDK 16 - C:\Program Files\Java\jdk-16
**Example for JDK 17 - C:\Program Files\Java\jdk-17
*Mac: /Library/Java/JavaVirtualMachines/jdk-{version}.jdk/Contents/Home
**Example for JDK 16 - /Library/Java/JavaVirtualMachines/jdk-16.jdk/Contents/Home
**Example for JDK 17 - /Library/Java/JavaVirtualMachines/jdk-17.jdk/Contents/Home
====Default Home Folder for JDK====
*Windows: C:\Program Files\Java\jdk-{version}\bin
**Example for JDK 16 - C:\Program Files\Java\jdk-16\bin
*Mac: /Library/Java/JavaVirtualMachines/jdk-{version}.jdk/Contents/Home/bin
**Example for JDK 16 - /Library/Java/JavaVirtualMachines/jdk-16.jdk/Contents/Home/bin
[[Category:Java]]