Keep Scrolling down for CS214 CheatSheet/Summary(Exceptions, Radio Buttons,...)
- Feel Free to Fork or Clone the Repository and Edit as u want.
- In case there is any Problem in my Code or if you want to Contribute, you can use GitHub issues or pull requests (Assuming you know Github), If no, U can reach out to me from the one who told you about this Repo.
Forward Iteration
itr.hasNext()true if there is a next element in the collection.itr.hasNext()Returns the next object.
Backward Iteration
itr.hasPrevious()true if there is a previous element.itr.previous()Returns the previous element.
Getting the Index of an Element
itr.nextIndex()Returns index of element that would be returned by subsequent call to next().itr.previousIndex()
- Testing if s2 is a subset of s1
s1.containsAll(s2)The answer is True or False - Setting s1 to the union of s1 and s2
s1.addAll(s2) - Setting s1 to the intersection of s1 and s2
s1.retainAll(s2) - Setting s1 to the difference of s1 and s2
s1.removeAll(s2)
if(post instanceof MessagePost )
MessagePost msg = ( MessagePost )
… access MessagePost methods via msg ...
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
public class RadioButton implements ActionListener{
static JRadioButton first;
static JRadioButton second;
static JTextField text;
public static void main(String[] args){
JFrame frame = new JFrame ("Radio Button");
frame.setSize(500,500);
frame.setBackground(Color.white);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
//Create a text field
text = new JTextField();
text.setBounds(0,0,500,50);
frame.add(text);
//Creat two radio Buttons
first = new JRadioButton("First");
second = new JRadioButton("Second");
first.setBounds(210, 100, 80, 60);
second.setBounds(210, 200, 80, 60);
frame.add(first);
frame.add(second);
//Create a radio Button Object
RadioButton obj = new RadioButton();
//Associate the radio buttons with ActionListener
first.addActionListener(obj);
second.addActionListener(obj);
//Display the Frame
frame.setVisible(true);
}
//Display the text of the selected Button
public void actionPerformed(ActionEvent e) {
String x = e.getActionCommand();
if (x.equals("First")) {
if (second.isSelected())
second.setSelected(false);
} else {
if (first.isSelected())
first.setSelected(false);
}
text.setText("The Button selected is: " + x);
}
}
import javax.swing.*;
public class CheckBoxExample {
CheckBoxExample() {
JFrame myFrame = new JFrame ("CheckBox Example ");
JCheckBox pythonCheckBox = new JCheckBox(" Python");
pythonCheckBox.setBounds(100, 100, 90, 90);
JCheckBox javaCheckBox = new JCheckBox("Java", true);
javaCheckBox.setBounds(100, 190, 90, 90);
myFrame.add(pythonCheckBox);
myFrame.add(javaCheckBox);
myFrame.setSize(400, 400);
myFrame.setLayout(null);
myFrame.setVisible(true);
}
public static void main(String[] arr){
new CheckBoxExample();
}
}
- Checked Exceptions: Checked for at Compile time.
- Unchecked exceptions: Aren't checked at Compile time.
IndexOutOfBoundsExceptionU have an array arr of length n ---> arr[n+2]IllegalArgumentExceptioncalling a method print(int value) with print();EOFExceptionAn end of file mark has been seen.ArithmeticExceptionDivision by zeroNumberFormatExceptionUsing Illegal Number Format, like using a float instead of integerNullPointerExceptiona class method is being called by an object instance that is currently null
throw!(in Methods), u can usethrow new Exception_type("Error Msg");throwsMethods throwing Checked Exception must havethrowsfor Exceptions that can be raised by a method.- U can use Multiple
catchstatements withtry - u can use
catchfor Multiple Options (1 || 2) finallyPerform any Common Actions whether an Exception is thrown or not, check Below:
try{
writingthisFile();
}
catch (FileNotFoundException e){
CatchtheMSGifUCan();
}
finally{ // الي مبين انه وجوده وعدمه واحد
closetheFile();
}
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