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import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
public class Example {
public static void main(String[] args) {
BufferedReader input = null;
BufferedWriter output = null;
try{
int c;
input = new BufferedReader(new FileReader("readfile.txt"));
output = new BufferedWriter(new FileWriter("writefile.txt"));
while ((c=input.read())!= -1) {
output.write(c);
}
} catch (FileNotFoundException fnfe){
System.err.println("The file was not found.");
fnfe.getMessage();
} catch (IOException ioe) {
System.err.println("The file could not be read.");
ioe.getMessage();
}finally {
try {
output.close();
} catch (IOException e) {
System.err.println("The file was not opened.");
e.printStackTrace();
}
try {
input.close();
} catch (IOException e) {
System.err.println("The file couldn't be closed.");
e.printStackTrace();
}
}
}
}
Der obige Code eine unerwartete Ausnahme auslöst - Nullpointer in einer der try-Block auf der folgenden Zeile: output.close() ;. Kann jemand den Grund dafür erklären? Jede Hilfe wäre willkommen. Danke im Voraus.unerwartete Ausnahme: java.lang.NullPointerException