Changing the way my program accepts files will create this error from GSON: Expected BEGIN_ARRAY but was BEGIN_OBJECT at line 1 column 2 path $?

Question

There's been a lot of questions asked about this topic but this question is different because the way I define a certain variable is what determines whether or not this error is thrown.

Basically, I have the below JSON file:

[
  {
    "appiumVersion":"1.8.1",
    "buildTag": "build-0",
    "newCommandTimeout": "30",
    "deviceName":"Samsung Galaxy S9 WQHD GoogleAPI Emulator",
    "deviceOrientation":"portrait",
    "browserName":"",
    "platformName":"Android",
    "platformVersion":"7.1",
    "app":"sauce-storage:ApiDemos-debug.apk"
  },
  {
    "appiumVersion":"1.8.1",
    "buildTag": "build-0",
    "newCommandTimeout": "30",
    "deviceName":"Samsung Galaxy S9 WQHD GoogleAPI Emulator",
    "deviceOrientation":"portrait",
    "browserName":"",
    "platformName":"Android",
    "platformVersion":"7.0",
    "app":"sauce-storage:ApiDemos-debug.apk"
  }
]

I am using GSON to parse it and this is the code for it:

File capsJsonFile = new File(capsFilePath);
Reader capsReader = null;

try {
    capsReader = new FileReader(capsJsonFile);
} catch (FileNotFoundException e) {
    e.printStackTrace();
}

Gson gsonCapsJsonArr = new Gson();

JsonObject[] capsJsonArr = gsonCapsJsonArr.fromJson(capsReader,  JsonObject[].class);

Then, I have another program that calls the above code:

capsFile = "C:\\Users\\exue\\IdeaProjects\\j-mobile\\tests\\src\\test\\resources\\capsJsonArray.json";
AutomationFramework.setCapsFilePath(capsFile);

And this code sets the "capsFilePath" variable equal to "capsFile".

What's weird is that if I write the program like this I have no error. But, I want to pass this capsFile string in as a system property through the maven-surefire-plugin that I am using to run this program, like so:

capsFile = System.getProperty("capsFile");
AutomationFramework.setCapsFilePath(capsFile);

I configured the plugin to look like so:

<plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-surefire-plugin</artifactId>
    <version>2.22.0</version>
    <configuration>
        <parallel>classes</parallel>
            <threadCount>4</threadCount>
        <redirectTestOutputToFile>false</redirectTestOutputToFile>
        <systemProperties>
            <property>
            <property>
                <name>capsFile</name>
                <value>C:\\Users\\exue\\IdeaProjects\\j-mobile\\tests\\src\\test\\resources\\cfgJsonFile.json</value>
            </property>
        </systemProperties>
    </configuration>
</plugin>

Having written it like this, taking the file as a system property, I now get this error:

[Utils] [ERROR] [Error] com.google.gson.JsonSyntaxException: java.lang.IllegalStateException: Expected BEGIN_ARRAY but was BEGIN_OBJECT at line 1 column 2 path $
        at com.google.gson.Gson.fromJson(Gson.java:939)
        at com.google.gson.Gson.fromJson(Gson.java:865)
        at com.transunion.qecop.automationframework.AutomationFramework.mobileDeviceDataProvider(AutomationFramework.java:208)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.lang.reflect.Method.invoke(Method.java:498)
        at org.testng.internal.MethodInvocationHelper.invokeMethod(MethodInvocationHelper.java:124)
        at org.testng.internal.MethodInvocationHelper.invokeMethod(MethodInvocationHelper.java:74)
        at org.testng.internal.MethodInvocationHelper.invokeMethodNoCheckedException(MethodInvocationHelper.java:45)
        at org.testng.internal.MethodInvocationHelper.invokeDataProvider(MethodInvocationHelper.java:131)
    at org.testng.internal.Parameters.handleParameters(Parameters.java:706)
    at org.testng.internal.ParameterHandler.handleParameters(ParameterHandler.java:49)
    at org.testng.internal.ParameterHandler.createParameters(ParameterHandler.java:37)
    at org.testng.internal.Invoker.invokeTestMethods(Invoker.java:924)
    at org.testng.internal.TestMethodWorker.invokeTestMethods(TestMethodWorker.java:125)
    at org.testng.internal.TestMethodWorker.run(TestMethodWorker.java:109)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
    at java.lang.Thread.run(Thread.java:748)
Caused by: java.lang.IllegalStateException: Expected BEGIN_ARRAY but was BEGIN_OBJECT at line 1 column 2 path $
at com.google.gson.stream.JsonReader.beginArray(JsonReader.java:350)
at com.google.gson.internal.bind.ArrayTypeAdapter.read(ArrayTypeAdapter.java:70)
at com.google.gson.Gson.fromJson(Gson.java:927)
... 19 more

But if I just hard-code the string, then this error does not occur. How could the way in which I feed in the file possibly cause this error?

score 1 · Accepted Answer · answered Aug 30 '18 at 15:48

The reason for this problem is that you are referring to two different JSON's

the one you are passing in string is capsJsonArray.json

whereas the one you are passing in maven is cfgJsonFile.json

I think the problem lies in json being refereed as it may be incorrect

Changing the way my program accepts files will create this error from GSON: Expected BEGIN_ARRAY but was BEGIN_OBJECT at line 1 column 2 path $?

1 Answers1