PropertiesEnhancer throwing a NPE on startup

[wyz]

Hi,

I have faced a strange issue with play. There is a UnexpectedError
caused by NPE when I first start up, however the application will run
as normal if I refresh it and the error is gone. My environment is
Ubuntu 10.04 64bit and Sun Java 6. The whole stacktrace is attached,
and any help will be appreciated.

Thanks.


Oops: UnexpectedException
An unexpected error occured caused by exception UnexpectedException:
Error in PropertiesEnhancer

play.exceptions.UnexpectedException: While applying class
play.classloading.enhancers.PropertiesEnhancer on
search.FullTextSearchPlugin
at play.classloading.ApplicationClasses
$ApplicationClass.enhance(ApplicationClasses.java:211)
at
play.classloading.ApplicationClassloader.loadApplicationClass(ApplicationClassloader.java:
125)
at
play.classloading.ApplicationClassloader.loadClass(ApplicationClassloader.java:
74)
at java.lang.ClassLoader.loadClass(ClassLoader.java:248)
at play.Play.start(Play.java:341)
at play.Play.detectChanges(Play.java:492)
at play.Invoker$Invocation.init(Invoker.java:98)
at Invocation.HTTP Request(Play!)
Caused by: play.exceptions.UnexpectedException: Error in
PropertiesEnhancer
at play.classloading.enhancers.PropertiesEnhancer
$1.edit(PropertiesEnhancer.java:139)
at javassist.expr.ExprEditor.loopBody(ExprEditor.java:197)
at javassist.expr.ExprEditor.doit(ExprEditor.java:90)
at javassist.CtBehavior.instrument(CtBehavior.java:618)
at
play.classloading.enhancers.PropertiesEnhancer.enhanceThisClass(PropertiesEnhancer.java:
100)
at play.classloading.ApplicationClasses
$ApplicationClass.enhance(ApplicationClasses.java:208)
... 7 more
Caused by: java.lang.NullPointerException
at java.io.ByteArrayInputStream.<init>(ByteArrayInputStream.java:89)
at play.classloading.enhancers.Enhancer
$ApplicationClassesClasspath.openClassfile(Enhancer.java:60)
at javassist.ClassPoolTail.openClassfile(ClassPoolTail.java:335)
at javassist.ClassPool.openClassfile(ClassPool.java:594)
at javassist.CtClassType.getClassFile2(CtClassType.java:185)
at javassist.CtClassType.makeFieldCache(CtClassType.java:760)
at javassist.CtClassType.getMembers(CtClassType.java:751)
at javassist.CtClassType.getDeclaredField2(CtClassType.java:873)
at javassist.CtClassType.getField2(CtClassType.java:828)
at javassist.CtClassType.getField(CtClassType.java:820)
at javassist.expr.FieldAccess.getField(FieldAccess.java:113)
at play.classloading.enhancers.PropertiesEnhancer
$1.edit(PropertiesEnhancer.java:107)
... 12 more

[Guillaume Bort]

I think that it is an old issue already fixed. What is your play version?

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[wyz]

I am running 1.0.2.1

[Guillaume Bort]

Well I don't know. Never saw that. Can you send me a simple app that
reproduce it?

[wyz]

I have tested with play 1.0.3 and the problem persists.

I tried to create a simple app to reproduce it but failed. I am not
able to give you my current project, but I am able to give you more
informations.

1. I have created a plugin called FullTextSearchPlugin, and I
configured it as "20:search.FullTextSearchPlugin" in play.plugins
2. Inside the FullTextSearchPlugin, I imported another class
"models.TagSubject"
3. The NPE is caused at line 60 in class Enhancer, it reads "new
ByteArrayInputStream(Play.classes.getApplicationClass(className).enhancedByteCode);"
4. At the time, className is "models.TagSubject",
Play.classes.getApplicationClass(className) evaluates to
"models.TagSubject (compiled:false) " and
Play.classes.getApplicationClass(className).enhancedByteCode is null,
which caused the NPE

Hope these information will help. Thanks.

On Jun 11, 11:53 pm, Guillaume Bort <guillaume.b...@gmail.com> wrote:
> Well I don't know. Never saw that. Can you send me a simple app that
> reproduce it?
>
>
>
> On Fri, Jun 11, 2010 at 4:41 AM,wyz<wangyiz...@gmail.com> wrote:
> > I am running 1.0.2.1
>
> > On Jun 10, 7:23 pm, Guillaume Bort <guillaume.b...@gmail.com> wrote:
> >> I think that it is an old issue already fixed. What is your play version?
>

[Guillaume Bort]

Please show me the code of the plugin. There is surely something bad
in the lifecycle.

[Tony Xiao]

I also run into this very same issue in Play 1.2.  Here's the code from the Plugin (still work in progress, lots of snippets experimenting everywhere. ) Basically I didn't like how JPA binds model objects and tried to intercept it myself.  But on class start i would get some exceptions. 

package com.tulsi.binders;

import java.lang.annotation.Annotation;

import java.lang.reflect.Field;

import java.lang.reflect.Modifier;

import java.lang.reflect.Type;

import java.util.Arrays;

import java.util.Map;

import org.json.simple.JSONObject;

import org.json.simple.JSONValue;

import models.BaseModel;

import models.autoup.IB;

import play.Logger;

import play.PlayPlugin;

import play.data.binding.BeanWrapper;

public class TulsiBinderPlugin extends PlayPlugin {

public static BeanWrapper ibWrapper = new BeanWrapper(IB.class);

@Override

public Object bind(String name, Class clazz, Type type,

Annotation[] annotations, Map<String, String[]> params) {

// debug(name, clazz, type, annotations, params);

Class sc = clazz.getSuperclass();

if (sc != null && sc.getCanonicalName().equals(BaseModel.class.getCanonicalName())) {

Logger.debug("BaseModel intercepted by TulsiBinder");

if (clazz.getName().equals(IB.class.getName()))

return bindIB(name, type, annotations, params);

}

// if (clazz.getName().equals(models.autoup.IB.class.getName())) {

// IB i = new IB();

// i.contractId =2323232;

// return i;

// IB i = IB.all().first();

// return i;

// }

return null;

}

public IB bindIB(String name, Type type,

Annotation[] annotations, Map<String, String[]> params) {

IB ib;

try {

ib = (IB) ibWrapper.bind(name, type, params, "", annotations);

} catch (Exception e) {

// TODO Auto-generated catch block

e.printStackTrace();

ib = new IB();

}

//new IB();

ib.localSymbol = "";

for (String key : params.keySet()) {

ib.localSymbol += key + "\n";

ib.localSymbol += "\t" + Arrays.asList(params.get(key)) + "\n";

}

if (params.get("ib") != null) {

JSONObject obj = (JSONObject) JSONValue.parse(params.get("ib")[0]);

ib.localSymbol += "\n json object starts here\n\n";

ib.localSymbol += obj.toJSONString();

}

        if (true)

return ib;

        Field fieldlist[] = IB.class.getDeclaredFields();

        for (int i = 0; i < fieldlist.length; i++) {

           Field fld = fieldlist[i];

           System.out.println("name = " + fld.getName());

           System.out.println("decl class = " + fld.getDeclaringClass());

           System.out.println("type = " + fld.getType());

           int mod = fld.getModifiers();

           System.out.println("modifiers = " + Modifier.toString(mod));

           System.out.println("-----");

        }

return null;

}

private void debug(String name, Class clazz, Type type,

Annotation[] annotations, Map<String, String[]> params) {

System.out.println("Name : " + name );

System.out.println(type.getClass());

System.out.println(clazz.getSuperclass());

for (String key : params.keySet()) {

System.out.println(key);

System.out.println(Arrays.asList(params.get(key)));

}

System.out.println("annotations");

System.out.println(Arrays.asList(annotations));

}

}

Oops: UnexpectedException

An unexpected error occured caused by exception UnexpectedException: While applying class play.classloading.enhancers.Pr

opertiesEnhancer on com.tulsi.binders.TulsiBinderPlugin

play.exceptions.UnexpectedException: While applying play.CorePlugin@317cfd38 on com.tulsi.binders.TulsiBinderPlugin

        at play.plugins.PluginCollection.enhance(PluginCollection.java:436)

        at play.classloading.ApplicationClasses$ApplicationClass.enhance(ApplicationClasses.java:208)

        at play.classloading.ApplicationClassloader.loadApplicationClass(ApplicationClassloader.java:151)

        at play.classloading.ApplicationClassloader.loadClass(ApplicationClassloader.java:84)

        at java.lang.ClassLoader.loadClass(ClassLoader.java:248)

        at play.plugins.PluginCollection.reloadApplicationPlugins(PluginCollection.java:141)

        at play.Play.start(Play.java:418)

        at play.Play.detectChanges(Play.java:569)

        at play.Invoker$Invocation.init(Invoker.java:186)

        at Invocation.HTTP Request(Play!)

Caused by: play.exceptions.UnexpectedException: While applying class play.classloading.enhancers.PropertiesEnhancer on c

om.tulsi.binders.TulsiBinderPlugin

        at play.CorePlugin.enhance(CorePlugin.java:297)

        at play.plugins.PluginCollection.enhance(PluginCollection.java:433)

        ... 9 more

Caused by: play.exceptions.UnexpectedException: Error in PropertiesEnhancer

        at play.classloading.enhancers.PropertiesEnhancer$1.edit(PropertiesEnhancer.java:171)

        at javassist.expr.ExprEditor.loopBody(ExprEditor.java:197)

        at javassist.expr.ExprEditor.doit(ExprEditor.java:90)

        at javassist.CtBehavior.instrument(CtBehavior.java:618)

        at play.classloading.enhancers.PropertiesEnhancer.enhanceThisClass(PropertiesEnhancer.java:129)

        at play.CorePlugin.enhance(CorePlugin.java:294)

        ... 10 more

Caused by: java.lang.NullPointerException

        at java.io.ByteArrayInputStream.<init>(ByteArrayInputStream.java:89)

        at play.classloading.enhancers.Enhancer$ApplicationClassesClasspath.openClassfile(Enhancer.java:60)

        at javassist.ClassPoolTail.openClassfile(ClassPoolTail.java:335)

        at javassist.ClassPool.openClassfile(ClassPool.java:594)

        at javassist.CtClassType.getClassFile2(CtClassType.java:185)

        at javassist.CtClassType.makeFieldCache(CtClassType.java:760)

        at javassist.CtClassType.getMembers(CtClassType.java:751)

        at javassist.CtClassType.getDeclaredField2(CtClassType.java:873)

        at javassist.CtClassType.getField2(CtClassType.java:828)

        at javassist.CtClassType.getField(CtClassType.java:820)

        at javassist.expr.FieldAccess.getField(FieldAccess.java:113)

        at play.classloading.enhancers.PropertiesEnhancer$1.edit(PropertiesEnhancer.java:136)

        ... 15 more

[robfig]

I have run into very similar errors when I accidentally had duplicate .class files in Play!'s classpath.  You may want to ensure that there is exactly one TulsiBinderPlugin.class file ..

The second thing I would try is making ibWrapper not a static member (e.g. creating a new one for every invocation), just to see if that makes the error go away.

(public static BeanWrapper ibWrapper = new BeanWrapper(IB.class);)