Need Help as to NullPointer Exception Possibilities

[Steve Dyke]

The following line of code is throwing the NullPointer Exception.

I have verified that the client code requesting the Servlet that calls the class has the badgenumber variable.

error:
java.lang.NullPointerException
[10/14/16 0:12:55:357 CDT] 00000088 SystemErr     R at com.FAIWebApp.logonconnections.LogOn.<init>(LogOn.java:60)
[10/14/16 0:12:55:357 CDT] 00000088 SystemErr     R at com.FAIWebApp.logonconnections.LogonControllerServlet.doPost(LogonControllerServlet.java:172)

js:

$.post("/QMSWebApp/LogonControllerServlet",
							{lifecycle:"logon",
							badgenumber:v1,
							password:v2,
							logontype:"Secure"},getLogOnResults, 'json');

global:

public final static String QMS_ALLOWED_CHARS = "[^a-zA-Z0-9:=+-;&%@#()\\[\\]±Ø°\040]";

servlet:

else if(lifecycle.equals("logon")){
				
				LogOn logon = null;
				User user = null;
				NavigationMenu navmenu = null;
172				logon = new LogOn(request, m, dft);

...

logon class:

try{
			if(iLogonType.equals("Guest")){
				iNavigationMenuSource = 1;
				userObject = new User();
				iLogOnMessage = "NoError";
			
			}
			else{
				iNavigationMenuSource = 2;
				
60				iBadgeNumber = request.getParameter("badgenumber").replaceAll(GenericParams.QMS_ALLOWED_CHARS, "");
			
...

[Campbell Ritchie]

Steve Dyke wrote:. . . .

// ...				
60   iBadgeNumber = request.getParameter("badgenumber").replaceAll(GenericParams.QMS_ALLOWED_CHARS, "");
			
// ...

So it is that line that causes the Exception to be thrown? And it is a java.lang.NullPointerException so it probably isn't thrown by the the JS code. In that line, there are several things which might be null:-

request

the return value from getParameter

QMS_ALLOWED_CHARS. Since you have showed where that is created, you can be >99% sure this isn't the culprit.

Or is the problem on this line?logon = new LogOn(request, m, dft);Is there any chance that any of request, m or dft is null? In which case does that constructor ever throw such an Exception?

I presume you know how to identify nulls with printf and the %b tag?System.out.printf("request != null: %b%n returned value != null: %b%n",   request, request.getParameter("badgenumber")); iBadgeNumber = // ...

[Steve Dyke]

Campbell Ritchie wrote:

Steve Dyke wrote:. . . .

// ...				
60   iBadgeNumber = request.getParameter("badgenumber").replaceAll(GenericParams.QMS_ALLOWED_CHARS, "");
			
// ...

So it is that line that causes the Exception to be thrown? And it is a java.lang.NullPointerException so it probably isn't thrown by the the JS code. In that line, there are several things which might be null:-

request

the return value from getParameter

QMS_ALLOWED_CHARS. Since you have showed where that is created, you can be >99% sure this isn't the culprit.

Or is the problem on this line?logon = new LogOn(request, m, dft);Is there any chance that any of request, m or dft is null? In which case does that constructor ever throw such an Exception?

I presume you know how to identify nulls with printf and the %b tag?System.out.printf("request != null: %b%n returned value != null: %b%n",   request, request.getParameter("badgenumber")); iBadgeNumber = // ...

First thanks for your time and help.

I do not see how, if the exception is being generated from a client request that the request could be null.

And no, I am not familiar with the 'how to identify nulls with printf and the %b tag', sorry.

[Junilu Lacar]

Steve Dyke wrote:System.out.printf("request != null: %b%n returned value != null: %b%n",   request, request.getParameter("badgenumber"));...
And no, I am not familiar with the 'how to identify nulls with printf and the %b tag', sorry.

Well, that's the code to do it. If you care to learn more, here's the documentation that explains how it works: https://docs.oracle.com/javase/7/docs/api/java/util/Formatter.html