Hi Chris, I did start off with a List<String> implementation but started changing stuff around in futile attempts to get something working. Anyway I tried your suggestion, and am still getting the same error:
//I've a whole bunch of different fields here cause i was testing various things, but "arrayListStr" follows your recommendation public class Test { private String name; private String description; private List countries; private String[] array; private TestChild testChild; private ArrayList arrayList; private List<String> arrayListStr; public Test() { arrayList = new ArrayList(); arrayListStr = new ArrayList<String>(); } public String getName() { return name; } public void setName(String name) { System.out.println("setting name"); this.name = name; } public String getDescription() { System.out.println("getting desc"); return description; } public void setDescription(String description) { System.out.println("settings description"); this.description = description; } public List getCountries() { return countries; } public void setCountries(List countries) { System.out.println("settings countries"); this.countries = countries; } public TestChild getTestChild() { return testChild; } public void setTestChild(TestChild testChild) { System.out.println("setting testchild"); this.testChild = testChild; } public String[] getArray() { return array; } public void setArray(String[] array) { System.out.println("setting arr"); this.array = array; } public ArrayList getArrayList() { return arrayList; } public void setArrayList(ArrayList arrayList) { System.out.println("setting arrlist"); this.arrayList = arrayList; } public List<String> getArrayListStr() { return arrayListStr; } public void setArrayListStr(List<String> arrayListStr) { System.out.println("setting arrliststr"); this.arrayListStr = arrayListStr; } } And the JSON: {"testChild": {"description":"kid"},"description":"whee", "name": "foo","array":["CA","SG"],"arrayListStr":["CA","SG"]} Thanks for your help! Shaun On Wed, Oct 10, 2012 at 11:33 PM, Chris Pratt <thechrispr...@gmail.com>wrote: > You *might* need to initialize the countries array. I wouldn't be > surprised if internally the JSON library is doing a > getCountries().add("CA") and throwing a null pointer exception because > getCountries is returning a null. > > Also, you should really be programming to interfaces, not implementations. > Define your methods to take and return the List<String> interface instead > of the ArrayList<String> specific implementation and your programs will be > much more flexible and reusable in the future. See if this works better: > (*Chris*) > > public class Test { > private String name; > private String description; > private List<String> countries; > > public Test() { > countries = new ArrayList<>(); > } > > public String getName() { > return name; > } > > public void setName(String name) { > this.name = name; > } > > public String getDescription() { > return description; > } > > public void setDescription(String description) { > this.description = description; > } > > public List<String> getCountries() { > return countries; > } > > public void setCountries(List<String> countries) { > this.countries = countries; > } > } > > On Wed, Oct 10, 2012 at 11:23 PM, Shaun Lim <shaunthegr...@gmail.com> > wrote: > > > My entity class: > > > > import java.util.ArrayList; > > > > > > public class Test { > > private String name; > > private String description; > > private ArrayList<String> countries; > > > > public Test() { > > > > } > > > > public String getName() { > > return name; > > } > > > > public void setName(String name) { > > this.name = name; > > } > > > > public String getDescription() { > > return description; > > } > > > > public void setDescription(String description) { > > this.description = description; > > } > > > > public ArrayList<String> getCountries() { > > return countries; > > } > > > > public void setCountries(ArrayList<String> countries) { > > this.countries = countries; > > } > > } > > > > The JSON I'm trying to send: > > > > {"countries": ["CA", "SG"], "description":"whee", "name": "foo"} > > > > The error: > > > > 2345447 [http-bio-8080-exec-1] ERROR freemarker.runtime - Method > > public java.lang.String > > > org.apache.commons.lang.exception.NestableRuntimeException.getMessage(int) > > threw an exception when invoked on net.sf.json.JSONException: Error > > while setting property=countries type interface java.util.List > > > > Method public java.lang.String > > > org.apache.commons.lang.exception.NestableRuntimeException.getMessage(int) > > threw an exception when invoked on net.sf.json.JSONException: Error > > while setting property=countries type interface java.util.List > > The problematic instruction: > > ---------- > > ==> ${msgs[0][0]} [on line 76, column 25 in > > org/apache/struts2/dispatcher/error.ftl] > > ---------- > > > > Java backtrace for programmers: > > ---------- > > freemarker.template.TemplateModelException: Method public > > java.lang.String > > > org.apache.commons.lang.exception.NestableRuntimeException.getMessage(int) > > threw an exception when invoked on net.sf.json.JSONException: Error > > while setting property=countries type interface java.util.List > > at > > freemarker.ext.beans.SimpleMethodModel.exec(SimpleMethodModel.java:130) > > at > > freemarker.ext.beans.SimpleMethodModel.get(SimpleMethodModel.java:138) > > at > > > freemarker.core.DynamicKeyName.dealWithNumericalKey(DynamicKeyName.java:111) > > at > > > freemarker.core.DynamicKeyName._getAsTemplateModel(DynamicKeyName.java:90) > > at freemarker.core.Expression.getAsTemplateModel(Expression.java:89) > > at freemarker.core.Expression.getStringValue(Expression.java:93) > > at freemarker.core.DollarVariable.accept(DollarVariable.java:76) > > at freemarker.core.Environment.visit(Environment.java:210) > > at freemarker.core.MixedContent.accept(MixedContent.java:92) > > at freemarker.core.Environment.visit(Environment.java:210) > > at freemarker.core.IfBlock.accept(IfBlock.java:82) > > at freemarker.core.Environment.visit(Environment.java:210) > > at freemarker.core.IfBlock.accept(IfBlock.java:82) > > at freemarker.core.Environment.visit(Environment.java:210) > > at freemarker.core.MixedContent.accept(MixedContent.java:92) > > at freemarker.core.Environment.visit(Environment.java:210) > > at freemarker.core.Environment.process(Environment.java:190) > > at freemarker.template.Template.process(Template.java:237) > > at > > org.apache.struts2.dispatcher.Dispatcher.sendError(Dispatcher.java:797) > > at > > > org.apache.struts2.dispatcher.Dispatcher.serviceAction(Dispatcher.java:519) > > at > > > org.apache.struts2.dispatcher.ng.ExecuteOperations.executeAction(ExecuteOperations.java:77) > > at > > > org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter.doFilter(StrutsPrepareAndExecuteFilter.java:91) > > at > > > org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243) > > at > > > org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210) > > at > > > org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:224) > > at > > > org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:175) > > at > > > org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:462) > > at > > > org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:164) > > at > > > org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:100) > > at > > org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:851) > > at > > > org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118) > > at > > > org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:405) > > at > > > org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:278) > > at > > > org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:515) > > at > > > org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:300) > > at > > > java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886) > > at > > > java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908) > > at java.lang.Thread.run(Thread.java:680) > > Caused by: java.lang.NullPointerException > > at > > > freemarker.ext.beans.SimpleMemberModel.unwrapArguments(SimpleMemberModel.java:85) > > at > > freemarker.ext.beans.SimpleMethodModel.exec(SimpleMethodModel.java:106) > > ... 37 more > > > > Setting "name" and "description" without attempting to pass in > "countries" > > work - the values are successfully mapped. > > > > Using the following XML works too: > > > > <com.foo.bar.entity.Test> > > <countries> > > <string>SG</string> > > </countries> > > <description>testt</description> > > </com.foo.bar.entity.Test> > > >