You seem to have forgotten to initialize the context member An Activity is a subclass of Context, so you don’t need to declare/initialize a separate Context to use. Instead just do; connManager = (ConnectivityManager)getSystemService(Context.CONNECTIVITY_SERVICE); 1 solved Weird nullpointer exception error [closed]
Use the new keyword for creating a J_Fish: J_Fish testForAnimal = new J_Fish(“Joe”, 2, 10); 0 solved java complie error：cannot find symbol
you can find some usages of most public api methods from grepcode. and here is yours. EDIT a running example may be like this import java.awt.Color; import java.awt.Graphics; import javax.swing.JFrame; import javax.swing.JLabel; import javax.swing.JPanel; import javax.swing.SwingUtilities; import javax.swing.border.LineBorder; public class Test { public static void main(String[] args) { SwingUtilities.invokeLater( () -> { JFrame frame = … Read more
If I understand your question, then this System.out.println(tot); System.out.print(a + b + c); should be System.out.print(tot); System.out.println(a + b + c); When I make the change above, I get output like you seem to be asking for – Number 1: 1 Number 2: 3 Number 3: 5 Total: 9 Another option would be to use … Read more
You seem to be asking about whether the above code is the correct way to write a method that overrides a method in its superclass. Yes it is the correct way to do it. Yes, that is a good way to “change behavior” … though you are only changing the behavior for the new class … Read more
The top level object in your JSON file is an array so: class letsRead { public static void main(String [] args) { String inline = “”; try { URL url = new URL(“https://gist.githubusercontent.com/anubhavshrimal/75f6183458db8c453306f93521e93d37/raw/f77e7598a8503f1f70528ae1cbf9f66755698a16/CountryCodes.json”); HttpURLConnection conn = (HttpURLConnection)url.openConnection(); conn.setRequestMethod(“GET”); conn.connect(); int responsecode = conn.getResponseCode(); System.out.println(“Response code is: ” +responsecode); if(responsecode != 200) throw new RuntimeException(“HttpResponseCode: ” … Read more
You should change this: @Override public Object getItem(int position) { return position; } @Override public long getItemId(int position) { return position; } solved Simple Displaying a list of Items Parsed from JSON [closed]
It looks like you stopped following the pattern that you applied in the beginning. As you’ll see, prior to line 310, you have used play = scan.nextLine(); if (play.charAt(0) == ‘x’ ) Where you call the scanner to read a new line before checking the character. After line 310, you have stopped using the play … Read more
Process aProcess = Runtime.getRuntime().exec(“cmd”); //you can pass any process here you can also read the output of this program. InputStream is = aProcess.getInputStream(); Ps: You can pass any process, along with the arguments, but you can’t pass things like >>, 2> or | or wild cards like * — from the comments 7 solved How … Read more
StringWriter sWriter = new StringWriter(); PrintWriter out = new PrintWriter(sWriter); out.println(“Hello World”); response.getWriter().print(sWriter.toString()); This creates a StringWriter that is independent of the response. It creates a String with the content you put in it and then takes that and puts it into PrintWriter of the response. PrintWriter out = response.getWriter(); This just gets the PrintWriter … Read more
You are getting StringIndexOutOfBoundsException because first thing in your while (number.charAt(0) != ‘0’ || number.length() < 4 || !number.matches(“^[0-9]*”) || number.isEmpty()) condition is number.charAt(0) which can throw exception if string is empty “”. To get rid of this problem move number.isEmpty() before number.charAt(0) != ‘0’. This is to validate a phone number that starts with … Read more
You will need an instance of your class on which you can call toString method : Manager m = new Manager(); … Set the value …. System.out.println(m.toString()); // or simply System.out.println(m); //this will indeed equal to call m.toString 0 solved Questions about a Java beginners [closed]
Looking quickly at the code, it would appear that the method is used to convert a String of bits representing a byte to an actual byte. For example, it would translate “1101” to a byte value 0x0D. It does this by analysing each individual character in the string, starting at the least significant character (ie: … Read more
You can use FileWriter and StringWriter together. public String FilesInFolder() throws IOException { FileWriter fw = new FileWriter(“file.txt”); StringWriter sw = new StringWriter(); // Will list all files in the directory, want to create a feature on the page that can display this to the user String path = NewDestination; System.out.println(“Starting searching files in directory”); … Read more
ActivityNotFoundException: Unable to find explicit activity class {co.edu.unimagdalena.projecto/co.edu.unimagdalena.projecto.informacion2} solved ActivityNotFoundException: Unable to find explicit activity class {co.edu.unimagdalena.projecto/co.edu.unimagdalena.projecto.informacion2}