java - Why can't I read an integer from a text file using a BufferedReader? -

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i can't read integer text file using bufferedreader:

bufferedreader br = new bufferedreader(new filereader("c:/heapsort.txt")); s = br.readline(); int x = integer.parseint(s);

the code above throws following exception:

ava.lang.numberformatexception: null     @ java.lang.integer.parseint(unknown source)     @ java.lang.integer.parseint(unknown source)     @ tester.main(tester.java:16)     @ sun.reflect.nativemethodaccessorimpl.invoke0(native method)     @ sun.reflect.nativemethodaccessorimpl.invoke(unknown source)     @ sun.reflect.delegatingmethodaccessorimpl.invoke(unknown source)     @ java.lang.reflect.method.invoke(unknown source)     @ edu.rice.cs.drjava.model.compiler.javaccompiler.runcommand(javaccompiler.java:272)

make sure value read file not null , integer. otherwise exception. because readline returns whole line file string


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