programmers vocabulary: February 2020

Saturday, February 29, 2020

Uncaught (in promise) SyntaxError: Unexpected end of JSON input

Error Blog

Hi Guys ,

This blog is about the error Uncaught (in promise) SyntaxError: Unexpected end of JSON input

Problem Statement

Unable to see the response from a http call in react js .

Error Details

error Log

ERROR DETAILS

Uncaught (in promise) SyntaxError: Unexpected end of JSON input
at <anonymous>:31:28

Solution

The http call does not return a json output . .

Code Changes

Please validate the API endpoint .

componentDidMount() {

        fetch(`/api/users`)

            .then(res => res.json())

            .then(result => this.setState({ users: result.users }))

}

OUTPUT

Thanks for reading . Let me know your thoughts in the comments below .

Inline Babel script: 'this' is not allowed before super()

Error Blog

Hi Guys ,

This blog is about the error Inline Babel script: 'this' is not allowed before super()

Problem Statement

Unable to load a html page in react js .

Error Details

error Log

ERROR DETAILS

babel.min.js:4 Uncaught SyntaxError: Inline Babel script: 'this' is not allowed before super()

3 | constructor() {

4 |

> 5 | this.state = {

| ^

6 | users: []

7 | }

8 | }

at r.buildCodeFrameError (babel.min.js:4)

at e.buildCodeFrameError (babel.min.js:23)

at e.ThisExpression (babel.min.js:7)

at e.o [as _call] (babel.min.js:22)

at e.a [as call] (babel.min.js:22)

at e.l [as visit] (babel.min.js:22)

at e.visitQueue (babel.min.js:22)

at e.visitSingle (babel.min.js:22)

at e.visit (babel.min.js:22)

at Function.v.node (babel.min.js:22)

Solution

As the error suggested , we modified the code and added super before using this .

Code Changes

List of files changed

constructor() {

        super();

        this.state = {

            users: []

        }

    }

OUTPUT

Thanks for reading . Let me know your thoughts in the comments below .

Node js Web Server

Start a http server using node js .

Install http-server

npm install http-server -g

Start it

cd MyApp

http-server

Starting up http-server, serving ./
Available on:
  http://192.138.1.4:8081
  http://169.214.159.112:8081
  http://127.0.0.1:8081
Hit CTRL-C to stop the server

Open the browser and type

http://192.138.1.4:8081

You can see the index.html file being served .

In the console you will see the following output :

[Sun Mar 01 2020 13:08:41 GMT+0530 (India Standard Time)]  "GET /" "Mozilla/5.0 (Linux; Android 8.0.0; moto x4) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/80.0.3987.119 Mobile Safari/537.36"
[Sun Mar 01 2020 13:08:42 GMT+0530 (India Standard Time)]  "GET /favicon.ico" "Mozilla/5.0 (Linux; Android 8.0.0; moto x4) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/80.0.3987.119 Mobile Safari/537.36"
[Sun Mar 01 2020 13:08:42 GMT+0530 (India Standard Time)]  "GET /favicon.ico" Error (404): "Not found"
[Sun Mar 01 2020 13:08:55 GMT+0530 (India Standard Time)]  "GET /FirstApp.html" "Mozilla/5.0 (Linux; Android 8.0.0; moto x4) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/80.0.3987.119 Mobile Safari/537.36"

Thursday, February 27, 2020

Sunday, February 23, 2020

Argument passed to when() is not a mock!

Error Blog

Hi Guys ,

This blog is about the error Argument passed to when() is not a mock! .

Problem Statement

This error will come when we try mock a class using Mockito and junit .

Error Details

error Log

ERROR DETAILS

org.mockito.exceptions.misusing.NotAMockException:

Argument passed to when() is not a mock!

Example of correct stubbing:

doThrow(new RuntimeException()).when(mock).someMethod();

at service.DbServiceTest.saveTest(DbServiceTest.java:20)

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.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:47)

at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)

at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:44)

at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)

at org.mockito.internal.runners.DefaultInternalRunner$1$1.evaluate(DefaultInternalRunner.java:44)

at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:271)

at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:70)

at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:50)

at org.junit.runners.ParentRunner$3.run(ParentRunner.java:238)

at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:63)

at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:236)

at org.junit.runners.ParentRunner.access$000(ParentRunner.java:53)

at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:229)

at org.junit.runners.ParentRunner.run(ParentRunner.java:309)

at org.mockito.internal.runners.DefaultInternalRunner$1.run(DefaultInternalRunner.java:74)

at org.mockito.internal.runners.DefaultInternalRunner.run(DefaultInternalRunner.java:80)

at org.mockito.internal.runners.StrictRunner.run(StrictRunner.java:39)

at org.mockito.junit.MockitoJUnitRunner.run(MockitoJUnitRunner.java:163)

at org.junit.runner.JUnitCore.run(JUnitCore.java:160)

at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:68)

at com.intellij.rt.execution.junit.IdeaTestRunner$Repeater.startRunnerWithArgs(IdeaTestRunner.java:47)

at com.intellij.rt.execution.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:242)

at com.intellij.rt.execution.junit.JUnitStarter.main(JUnitStarter.java:70)

Solution

What made this fix

Code Changes

List of files changed

OUTPUT

Result

Thanks for reading . Let me know your thoughts in the comments below .

Monday, February 17, 2020

Failed to bind properties under '' to com.zaxxer.hikari.HikariDataSource:

Error Blog

Hi Guys ,

This blog is about the error Failed to bind properties under '' to com.zaxxer.hikari.HikariDataSource:

Problem Statement

This error occurs while maven build of a spring boot project .

Error Details

error Log

ERROR DETAILS

Description:

Failed to bind properties under '' to com.zaxxer.hikari.HikariDataSource:

Property: driverclassname

Value: com.mysql.cj.jdbc.Driver

Origin: "driverClassName" from property source "source"

Reason: Failed to load driver class com.mysql.cj.jdbc.Driver in either of HikariConfig class loader or Thread context classloader

Action:

Update your application's configuration

2020-02-18 01:15:00.184 ERROR 14292 --- [ main] o.s.test.context.TestContextManager : Caught exception while allowing TestExecutionListener [org.springframework.test.context.web.ServletTestExecutionListener@54c5a2ff] to prepare test instance [dbtest.dbtest.DbtestApplicationTests@1436a7ab]

java.lang.IllegalStateException: Failed to load ApplicationContext

at org.springframework.test.context.cache.DefaultCacheAwareContextLoaderDelegate.loadContext(DefaultCacheAwareContextLoaderDelegate.java:132) ~[spring-test-5.2.3.RELEASE.jar:5.2.3.RELEASE]

at org.springframework.test.context.support.DefaultTestContext.getApplicationContext(DefaultTestContext.java:123) ~[spring-test-5.2.3.RELEASE.jar:5.2.3.RELEASE]

at org.springframework.test.context.web.ServletTestExecutionListener.setUpRequestContextIfNecessary(ServletTestExecutionListener.java:190) ~[spring-test-5.2.3.RELEASE.jar:5.2.3.RELEASE]

at org.springframework.test.context.web.ServletTestExecutionListener.prepareTestInstance(ServletTestExecutionListener.java:132) ~[spring-test-5.2.3.RELEASE.jar:5.2.3.RELEASE]

at org.springframework.test.context.TestContextManager.prepareTestInstance(TestContextManager.java:244) ~[spring-test-5.2.3.RELEASE.jar:5.2.3.RELEASE]

at org.springframework.test.context.junit.jupiter.SpringExtension.postProcessTestInstance(SpringExtension.java:98) [spring-test-5.2.3.RELEASE.jar:5.2.3.RELEASE]

at org.junit.jupiter.engine.descriptor.ClassBasedTestDescriptor.lambda$invokeTestInstancePostProcessors$5(ClassBasedTestDescriptor.java:337) [junit-jupiter-engine-5.5.2.jar:5.5.2]

at org.junit.jupiter.engine.descriptor.ClassBasedTestDescriptor.executeAndMaskThrowable(ClassBasedTestDescriptor.java:342) [junit-jupiter-engine-5.5.2.jar:5.5.2]

at org.junit.jupiter.engine.descriptor.ClassBasedTestDescriptor.lambda$invokeTestInstancePostProcessors$6(ClassBasedTestDescriptor.java:337) [junit-jupiter-engine-5.5.2.jar:5.5.2]

at java.util.stream.ReferencePipeline$3$1.accept(ReferencePipeline.java:193) ~[na:1.8.0_91]

at java.util.stream.ReferencePipeline$2$1.accept(ReferencePipeline.java:175) ~[na:1.8.0_91]

at java.util.ArrayList$ArrayListSpliterator.forEachRemaining(ArrayList.java:1374) ~[na:1.8.0_91]

at java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:481) ~[na:1.8.0_91]

at java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:471) ~[na:1.8.0_91]

at java.util.stream.StreamSpliterators$WrappingSpliterator.forEachRemaining(StreamSpliterators.java:312) ~[na:1.8.0_91]

at java.util.stream.Streams$ConcatSpliterator.forEachRemaining(Streams.java:743) ~[na:1.8.0_91]

at java.util.stream.Streams$ConcatSpliterator.forEachRemaining(Streams.java:742) ~[na:1.8.0_91]

at java.util.stream.ReferencePipeline$Head.forEach(ReferencePipeline.java:580) ~[na:1.8.0_91]

at org.junit.jupiter.engine.descriptor.ClassBasedTestDescriptor.invokeTestInstancePostProcessors(ClassBasedTestDescriptor.java:336) [junit-jupiter-engine-5.5.2.jar:5.5.2]

at org.junit.jupiter.engine.descriptor.ClassBasedTestDescriptor.instantiateAndPostProcessTestInstance(ClassBasedTestDescriptor.java:259) [junit-jupiter-engine-5.5.2.jar:5.5.2]

at org.junit.jupiter.engine.descriptor.ClassBasedTestDescriptor.lambda$testInstancesProvider$2(ClassBasedTestDescriptor.java:252) [junit-jupiter-engine-5.5.2.jar:5.5.2]

at java.util.Optional.orElseGet(Optional.java:267) ~[na:1.8.0_91]

at org.junit.jupiter.engine.descriptor.ClassBasedTestDescriptor.lambda$testInstancesProvider$3(ClassBasedTestDescriptor.java:251) [junit-jupiter-engine-5.5.2.jar:5.5.2]

at org.junit.jupiter.engine.execution.TestInstancesProvider.getTestInstances(TestInstancesProvider.java:29) ~[junit-jupiter-engine-5.5.2.jar:5.5.2]

at org.junit.jupiter.engine.descriptor.TestMethodTestDescriptor.lambda$prepare$0(TestMethodTestDescriptor.java:106) ~[junit-jupiter-engine-5.5.2.jar:5.5.2]