j2me function java.lang.nullpointerexception - what is wrong in this?
-
17-02-2021 - |
Pregunta
Yesterday Night, i wrote this function to fetch all the tags from string containing xml data but something is not correct in this... Pls help... this function is returning java.lang.NullPointerException
public void parseWebXML(String xd){
int i, j, k = 0;
String tagn, check = "";
int spos, epos;
byte[] len = xd.getBytes();
tags = new String[len.length*3/4];
int nextpos = 0;
for(i=0;i<len.length*3/4;i++){
spos = xd.indexOf("<", nextpos);
epos = xd.indexOf(">", spos);
tagn = xd.substring(spos, epos);
if(i == 0 || i == 1 || i == 2){
if(tagn.indexOf("/") == -1){
tags[k] = "<"+tagn+">";
k +=1;
}else{
continue;
}
}else{
if(tagn.indexOf("/") == -1){
for(j=0;j<tags.length;j++){
if(tags[i].equals(tags[j])){
check = "found";
}else{
check = "notfound";
}
}
if(check.equals("notfound")){
tags[i] = "<"+tagn+">";
k+=1;
}else{
continue;
}
}else{
continue;
}
}
nextpos = epos + 1;
}
}
error that i saw while executing in debugger mode
TRACE: <at java.lang.NullPointerException: 0>, Exception caught in Display class
java.lang.NullPointerException: 0
- httpcon.parseWebXML(), bci=170
Solución
You initialized tags[], but not each of its cells, so tags[i].equals(tags[j])
probably caused the NPE
(tags[i]
is null).
Otros consejos
tags[] has only 3 items.
if(i == 0 || i == 1 || i == 2){
if(tagn.indexOf("/") == -1){
tags[k] = "<"+tagn+">";
k +=1;
if i > 3 than tags[i] return null. And tags[i].equals throw NPE
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