NullPointer Exception in java code (getting Name of File:null output ) -
public class helloworld { public static int executelock; public static int val; public helloworld() { executelock = 0; val = 0; } public static void main(string[] args) throws exception { new helloworld(); new thread(new runnable() { public void run() { try{ webfsmanager wfm = new webfsmanager(); }catch(exception e) { e.printstacktrace(); } } }).start(); new thread(new runnable() { public void run() { try{ while(true){ thread.sleep(10); if(executelock>=2){ file f = new webfsfile("read.js"); system.out.println("name of file :"+f.tostring()); //fileinputstream f1 = new webfsfileinputstream(f); //f1.read(); //f.deleteonexit(); break; } } }catch(exception e) { e.printstacktrace(); } } }).start(); } } .........separate file........................... public class webfsfile extends file { string filename; boolean fileexists; public webfsfile(file parent, string child){super(parent,child);} public webfsfile(string parent, string child){super(parent,child);} public webfsfile(uri uri) {super(uri);} public webfsfile(string filename) { super(filename); string script = "<html><body>hello</body></html>" webfsmanager.writeinscriptqueue(script, false); string returnval = webfsmanager.readrawreplyqueue(); if(returnval.equals("error: file or directory not found")) { fileexists = false; } else if (integer.parseint(returnval)==1){ fileexists = true; } else{ throw new webfsclientsideexception(returnval); } this.filename = filename; if(this.filename == null){ throw new nullpointerexception("null object supplied in webfsfile constructor"); } } } webfsmanager serparate independent class run's jetty server.when instantiate webfsfile class object , catch file object jumps webfsfile constructor , delivers script webfsmanager , replys it.but getting name of file:null output. me
i changed but:
import java.io.*; public class take { public static void main(string a[]) { file t = new try1("hi"); system.out.println("name of file :"+t.tostring()); } public static class try1 extends file { public try1(string name) throws nullpointerexception { super(name); } } } output:
name of file :hi
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