java - Null Pointer Exception with objectinputstream -

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• what nullpointerexception, , how fix it? 12 answers

i'm trying read list of names , phone numbers in. the program keeps throwing nullpointerexception. why doing this?

int i=0;         datab[] b = null;          //b = null;          // name of file open.         string filename = "datt.dat";          try {             // use reading data.             byte[] buffer = new byte[1000];             fileinputstream fileis = new fileinputstream("datt.dat");             objectinputstream input = new objectinputstream(fileis);              for(i=0; i<b.length; i++)              b[i]=(datab)input.readobject();              input.close(); 

b null, b.length throws exception