I worked with Oracle for this project, and sometime i need to truncate and clean all my oracle database’s content. So instead of truncate the tables one by one, i found a simple query to generate a simple truncate query.
select 'truncate table ' || table_name || ';' from user_tables
Hope it helped others 🙂
This is an example of a simple hello world using Java.
interface Printer {
void print(Message message);
}
class Message {
private String message;
public Message(String message) {
this.message = message;
}
public void print(Printer printer) {
printer.print(this);
}
public String toString() {
return message;
}
}
abstract class AbstractPrinterFactory {
public static AbstractPrinterFactory getFactory(){
return new SystemOutPrinterFactory();
}
public abstract Printer getPrinter();
}
class SystemOutPrinterFactory extends AbstractPrinterFactory {
public Printer getPrinter() {
return new SystemOutPrinter();
}
}
class SystemOutPrinter implements Printer {
public void print(Message message) {
System.out.println(message);
}
}
public class HelloWorld {
public static void main(String[] args) {
Message message = new Message("Hello, World!");
AbstractPrinterFactory factory = AbstractPrinterFactory.getFactory();
Printer printer = factory.getPrinter();
message.print(printer);
}
}
Just for fun (H)
On my latest project, i need to connect my java application to a GSM Modem, in order to sending and receiving SMS text. But before my application connected to opened comm port, i need to check which port number is opened. So this is a small java class to check my opened comm port. Btw, im using rtxt libraries to help me communicate with the opened port.
import gnu.io.CommPortIdentifier;
import java.util.Enumeration;
public class Main {
private void doSomething() {
Enumeration portList = CommPortIdentifier.getPortIdentifiers();
System.out.println(portList.hasMoreElements());
while (portList.hasMoreElements()) {
CommPortIdentifier portId = (CommPortIdentifier) portList.nextElement();
System.out.println(portId.getName());
}
}
public static void main(String[] args) {
Main main = new Main();
main.doSomething();
}
}
Dont forget to add rxtx libraries your java’s path. You can find the Window’s installation path, here.
Hope it helps other, have fun 🙂
I found this weird exception when im trying to convert double values to BigDecimal,
java.lang.ArithmeticException: Rounding necessary at java.math.BigDecimal.divideAndRound(BigDecimal.java:1439) at java.math.BigDecimal.setScale(BigDecimal.java:2394) at java.math.BigDecimal.setScale(BigDecimal.java:2437)
This is my java code
BigDecimal bgAvg = new BigDecimal(0); bgAvg = bgAvg.add(new BigDecimal(myDoubleValue).setScale(2));
Somehow the error is gone after i changed my code into this
BigDecimal bgAvg = new BigDecimal(0); bgAvg = bgAvg.add(BigDecimal.valueOf(myDoubleValue).setScale(2));
Hope it helped others, have fun with Java 😉
This is a simple method to create a random string result, the first method is create string between A-Z and 0-9 while the second one only provide hexadecimal characters.
package com.edw.main;
import java.util.UUID;
import org.apache.commons.lang.RandomStringUtils;
public class Main {
public static void main(String[] args) {
// one
System.out.println(RandomStringUtils.randomAlphanumeric(32).toUpperCase());
// two
System.out.println(UUID.randomUUID().toString().replace("-", "").toUpperCase());
}
}
This is the screenshot of my Netbeans Project.
and this is the result,
Hope it helped others, good luck.