Urgently seek the solution of this code

Question

this code is using the SOAP for message transmission
class checkData is on the server side, fetch information from database.
class Transport is on the client side, make the SOAP "call"
I use UtilSnoop to fetch the message between server and client, we can see that seems the checkData class works well, it can get the information from database and seems it can transmit it back. but when the progress come back Transport class, I found it failure in excute this line:
--- resp = call.invoke(url, ""); ---
the error message is : java.NullPointerException
the result from the XML message fetched by UtilSNoop, and the error message, looks inconsistent, what was the problem, plesase help me
public class Transport {
public Object[][] doTran_viewList () throws Exception {
Object [][] value=null;
try{
url=new URL(log.urls);
SOAPMappingRegistry smr = new SOAPMappingRegistry();
BeanSerializer beanSer = new BeanSerializer();
Call call = new Call ();
call.setTargetObjectURI ("urn:RegistrySystem");
call.setMethodName ("ViewList");
call.setEncodingStyleURI(Constants.NS_URI_SOAP_ENC);
Vector params = new Vector ();
String arg1=" ";
params.addElement (new Parameter("arg1", String.class,arg1, null));
call.setParams (params);
Response resp;
System.out.println("before");//when run this code, it will print out "before"
resp = call.invoke(url, "");
System.out.println("after");//but no after
if (!resp.generatedFault())
Parameter ret = resp.getReturnValue();
value = (Object[][])ret.getValue();
else
Fault fault = resp.getFault();
System.err.println("Generated fault: " + fault);
return value;
}catch(Exception e){
System.err.println("fail to build call");//when run, it will print out this
return value;
public class checkData{
public Object[][] ViewList (String arg1) throws IllegalArgumentException{
int p=0;
String url="jdbc:odbc:RST";
String cs="select ID,Name from course";
Connection con=null;
Statement stmt=null;
ResultSet rs =null;
try {
Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
} catch(java.lang.ClassNotFoundException e) {
System.err.print("ClassNotFoundException:");
System.err.println(e.getMessage());
try {
con=DriverManager.getConnection(url);
stmt=con.createStatement();
rs=stmt.executeQuery(cs);
while(rs.next()){p++;}
} catch(SQLException ex) {
System.err.println("SQLException: "+ex.getMessage());
Object[][] value = new Object[p][2];
try {
con=DriverManager.getConnection(url);
stmt=con.createStatement();
rs=stmt.executeQuery(cs);
for(p=0;rs.next();p++) {
String i = rs.getString("ID");
String n = rs.getString("Name");
value[p][0] =i;
value[p][1] =n;
stmt.close();
con.close();
} catch(SQLException ex) {
System.err.println("SQLException: "+ex.getMessage());
finally{
if (rs!=null) {
try {
rs.close();
} catch (Exception ex) {
} //end of if(rs)
if (stmt!=null) {
try {
stmt.close();
} catch (Exception ex) {
}//end of if(stm)
if (con!=null) {
try {
con.close();
} catch (Exception ex) {
}//end of if(con)
return value;
the UtilSnoop fetch message from server to client:
<?xml version='1.0' encoding='UTF-8'?>
<SOAP-ENV:Envelope xmlns:SOAP-ENV="http://schemas.xmlsoap.org/soap/envelope/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema">
<SOAP-ENV:Body>
<ns1:ViewListResponse xmlns:ns1="urn:RegistrySystem" SOAP-ENV:encodingStyle="http://schemas.xmlsoap.org/soap/encoding/">
<return xmlns:ns2="http://schemas.xmlsoap.org/soap/encoding/" xsi:type="ns2:Array" ns2:arrayType="ns2:Array[13]">
<item xsi:type="ns2:Array" ns2:arrayType="xsd:anyType[2]">
<item xsi:type="xsd:string">IEI22202</item>
<item xsi:type="xsd:string">GUI</item>
</item>
<item xsi:type="ns2:Array" ns2:arrayType="xsd:anyType[2]">
<item xsi:type="xsd:string">IEI12301</item>
<item xsi:type="xsd:string">Robotics</item>
</item>
</return>
</ns1:ViewListResponse>
</SOAP-ENV:Body>
</SOAP-ENV:Envelope>

Answer 1

First make sure that you deployed urn:RegistrySystem. I do this from the soap admin page.
If you have narrowed down that the NullPointerException is coming from the call.innvoke() line, then I would make sure that your URL is not null.
You did: url=new URL(log.urls);
I am not sure what log.urls is, but I would so a simple check to see if url is null after this statement. If it is, then you narrowed down your problem.
this code is using the SOAP for message transmission
class checkData is on the server side, fetch
information from database.
class Transport is on the client side, make the SOAP
"call"
I use UtilSnoop to fetch the message between server
and client, we can see that seems the checkData class
works well, it can get the information from database
and seems it can transmit it back. but when the
progress come back Transport class, I found it failure
in excute this line:
--- resp = call.invoke(url, ""); ---
the error message is : java.NullPointerException
the result from the XML message fetched by UtilSNoop,
and the error message, looks inconsistent, what was
the problem, plesase help me
public class Transport {
public Object[][] doTran_viewList () throws Exception
Object [][] value=null;
try{
url=new URL(log.urls);
SOAPMappingRegistry smr = new SOAPMappingRegistry();
BeanSerializer beanSer = new BeanSerializer();
Call call = new Call ();
call.setTargetObjectURI ("urn:RegistrySystem");
call.setMethodName ("ViewList");
call.setEncodingStyleURI(Constants.NS_URI_SOAP_ENC);
Vector params = new Vector ();
String arg1=" ";
params.addElement (new Parameter("arg1",
String.class,arg1, null));
call.setParams (params);
Response resp;
System.out.println("before");//when run this code, it
will print out "before"
resp = call.invoke(url, "");
System.out.println("after");//but no after
if (!resp.generatedFault())
Parameter ret = resp.getReturnValue();
value = (Object[][])ret.getValue();
else
Fault fault = resp.getFault();
System.err.println("Generated fault: " + fault);
return value;
}catch(Exception e){
System.err.println("fail to build call");//when run,
it will print out this
return value;
public class checkData{
public Object[][] ViewList (String arg1) throws
IllegalArgumentException{
int p=0;
String url="jdbc:odbc:RST";
String cs="select ID,Name from course";
Connection con=null;
Statement stmt=null;
ResultSet rs =null;
try {
Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
} catch(java.lang.ClassNotFoundException e) {
System.err.print("ClassNotFoundException:");
System.err.println(e.getMessage());
try {
con=DriverManager.getConnection(url);
stmt=con.createStatement();
rs=stmt.executeQuery(cs);
while(rs.next()){p++;}
} catch(SQLException ex) {
System.err.println("SQLException: "+ex.getMessage());
Object[][] value = new Object[p][2];
try {
con=DriverManager.getConnection(url);
stmt=con.createStatement();
rs=stmt.executeQuery(cs);
for(p=0;rs.next();p++) {
String i = rs.getString("ID");
String n = rs.getString("Name");
value[p][0] =i;
value[p][1] =n;
stmt.close();
con.close();
} catch(SQLException ex) {
System.err.println("SQLException: "+ex.getMessage());
finally{
if (rs!=null) {
try {
rs.close();
} catch (Exception ex) {
} //end of if(rs)
if (stmt!=null) {
try {
stmt.close();
} catch (Exception ex) {
}//end of if(stm)
if (con!=null) {
try {
con.close();
} catch (Exception ex) {
}//end of if(con)
return value;
the UtilSnoop fetch message from server to client:
<?xml version='1.0' encoding='UTF-8'?>
<SOAP-ENV:Envelope
xmlns:SOAP-ENV="http://schemas.xmlsoap.org/soap/envelop
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:xsd="http://www.w3.org/2001/XMLSchema">
<SOAP-ENV:Body>
<ns1:ViewListResponse xmlns:ns1="urn:RegistrySystem"
SOAP-ENV:encodingStyle="http://schemas.xmlsoap.org/soap
encoding/">
<return
xmlns:ns2="http://schemas.xmlsoap.org/soap/encoding/"
xsi:type="ns2:Array" ns2:arrayType="ns2:Array[13]">
<item xsi:type="ns2:Array"
ns2:arrayType="xsd:anyType[2]">
<item xsi:type="xsd:string">IEI22202</item>
<item xsi:type="xsd:string">GUI</item>
</item>
<item xsi:type="ns2:Array"
ns2:arrayType="xsd:anyType[2]">
<item xsi:type="xsd:string">IEI12301</item>
<item xsi:type="xsd:string">Robotics</item>
</item>
</return>
</ns1:ViewListResponse>
</SOAP-ENV:Body>
</SOAP-ENV:Envelope>