Spring-boot: Spring fails to start if '@' simbol used in yml config file

[ufoscout]

Spring boot fails to start with the following error if a '@' symbol is found in the yml configuration file:

15:56:35.328 [main] ERROR org.springframework.boot.SpringApplication - Application startup failed
org.yaml.snakeyaml.scanner.ScannerException: while scanning for the next token
found character '@' that cannot start any token. (Do not use @ for indentation)
 in 'reader', line 4, column 21:
        revision:       @buildNumber@
                        ^

    at org.yaml.snakeyaml.scanner.ScannerImpl.fetchMoreTokens(ScannerImpl.java:420)
    at org.yaml.snakeyaml.scanner.ScannerImpl.checkToken(ScannerImpl.java:226)

We have some configuration values provided by maven, they are marked by the '@' character as indicated in the spring boot documentation. However, some of those values are replaced only at release time so they are not present when using the spring-boot plugin to run the application of when tests are executed.

Environment:
spring-boot version: 1.5.1
openjdk version "1.8.0_121" 64 bit
Ubuntu 16.04 64bit

Full exception stacktrace when running the unit tests:

15:56:35.328 [main] ERROR org.springframework.boot.SpringApplication - Application startup failed
org.yaml.snakeyaml.scanner.ScannerException: while scanning for the next token
found character '@' that cannot start any token. (Do not use @ for indentation)
 in 'reader', line 4, column 21:
        revision:       @buildNumber@
                        ^

    at org.yaml.snakeyaml.scanner.ScannerImpl.fetchMoreTokens(ScannerImpl.java:420)
    at org.yaml.snakeyaml.scanner.ScannerImpl.checkToken(ScannerImpl.java:226)
    at org.yaml.snakeyaml.parser.ParserImpl$ParseBlockMappingValue.produce(ParserImpl.java:585)
    at org.yaml.snakeyaml.parser.ParserImpl.peekEvent(ParserImpl.java:157)
    at org.yaml.snakeyaml.parser.ParserImpl.checkEvent(ParserImpl.java:147)
    at org.yaml.snakeyaml.composer.Composer.composeNode(Composer.java:132)
    at org.yaml.snakeyaml.composer.Composer.composeValueNode(Composer.java:246)
    at org.yaml.snakeyaml.composer.Composer.composeMappingChildren(Composer.java:237)
    at org.yaml.snakeyaml.composer.Composer.composeMappingNode(Composer.java:225)
    at org.yaml.snakeyaml.composer.Composer.composeNode(Composer.java:155)
    at org.yaml.snakeyaml.composer.Composer.composeValueNode(Composer.java:246)
    at org.yaml.snakeyaml.composer.Composer.composeMappingChildren(Composer.java:237)
    at org.yaml.snakeyaml.composer.Composer.composeMappingNode(Composer.java:225)
    at org.yaml.snakeyaml.composer.Composer.composeNode(Composer.java:155)
    at org.yaml.snakeyaml.composer.Composer.composeDocument(Composer.java:122)
    at org.yaml.snakeyaml.composer.Composer.getNode(Composer.java:84)
    at org.yaml.snakeyaml.constructor.BaseConstructor.getData(BaseConstructor.java:104)
    at org.yaml.snakeyaml.Yaml$1.next(Yaml.java:471)
    at org.springframework.beans.factory.config.YamlProcessor.process(YamlProcessor.java:160)
    at org.springframework.beans.factory.config.YamlProcessor.process(YamlProcessor.java:138)
    at org.springframework.boot.env.YamlPropertySourceLoader$Processor.process(YamlPropertySourceLoader.java:101)
    at org.springframework.boot.env.YamlPropertySourceLoader.load(YamlPropertySourceLoader.java:58)
    at org.springframework.boot.env.PropertySourcesLoader.load(PropertySourcesLoader.java:127)
    at org.springframework.boot.context.config.ConfigFileApplicationListener$Loader.loadIntoGroup(ConfigFileApplicationListener.java:472)
    at org.springframework.boot.context.config.ConfigFileApplicationListener$Loader.load(ConfigFileApplicationListener.java:459)
    at org.springframework.boot.context.config.ConfigFileApplicationListener$Loader.load(ConfigFileApplicationListener.java:380)
    at org.springframework.boot.context.config.ConfigFileApplicationListener.addPropertySources(ConfigFileApplicationListener.java:215)
    at org.springframework.boot.context.config.ConfigFileApplicationListener.postProcessEnvironment(ConfigFileApplicationListener.java:184)
    at org.springframework.boot.context.config.ConfigFileApplicationListener.onApplicationEnvironmentPreparedEvent(ConfigFileApplicationListener.java:171)
    at org.springframework.boot.context.config.ConfigFileApplicationListener.onApplicationEvent(ConfigFileApplicationListener.java:157)
    at org.springframework.context.event.SimpleApplicationEventMulticaster.invokeListener(SimpleApplicationEventMulticaster.java:167)
    at org.springframework.context.event.SimpleApplicationEventMulticaster.multicastEvent(SimpleApplicationEventMulticaster.java:139)
    at org.springframework.context.event.SimpleApplicationEventMulticaster.multicastEvent(SimpleApplicationEventMulticaster.java:122)
    at org.springframework.boot.context.event.EventPublishingRunListener.environmentPrepared(EventPublishingRunListener.java:73)
    at org.springframework.boot.SpringApplicationRunListeners.environmentPrepared(SpringApplicationRunListeners.java:54)
    at org.springframework.boot.SpringApplication.prepareEnvironment(SpringApplication.java:336)
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:307)
    at org.springframework.boot.test.context.SpringBootContextLoader.loadContext(SpringBootContextLoader.java:120)
    at org.springframework.test.context.cache.DefaultCacheAwareContextLoaderDelegate.loadContextInternal(DefaultCacheAwareContextLoaderDelegate.java:98)
    at org.springframework.test.context.cache.DefaultCacheAwareContextLoaderDelegate.loadContext(DefaultCacheAwareContextLoaderDelegate.java:116)
    at org.springframework.test.context.support.DefaultTestContext.getApplicationContext(DefaultTestContext.java:83)
    at org.springframework.boot.test.autoconfigure.SpringBootDependencyInjectionTestExecutionListener.prepareTestInstance(SpringBootDependencyInjectionTestExecutionListener.java:47)
    at org.springframework.test.context.TestContextManager.prepareTestInstance(TestContextManager.java:230)
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.createTest(SpringJUnit4ClassRunner.java:228)
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner$1.runReflectiveCall(SpringJUnit4ClassRunner.java:287)
    at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.methodBlock(SpringJUnit4ClassRunner.java:289)
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:247)
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:94)
    at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
    at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
    at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
    at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
    at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
    at org.springframework.test.context.junit4.statements.RunBeforeTestClassCallbacks.evaluate(RunBeforeTestClassCallbacks.java:61)
    at org.springframework.test.context.junit4.statements.RunAfterTestClassCallbacks.evaluate(RunAfterTestClassCallbacks.java:70)
    at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.run(SpringJUnit4ClassRunner.java:191)
    at org.junit.runners.Suite.runChild(Suite.java:128)
    at org.junit.runners.Suite.runChild(Suite.java:27)
    at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
    at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
    at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
    at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
    at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
    at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
    at org.junit.extensions.cpsuite.ClasspathSuite.run(ClasspathSuite.java:196)
    at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:86)
    at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:459)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:678)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:382)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:192)
15:56:35.328 [main] ERROR org.springframework.test.context.TestContextManager - Caught exception while allowing TestExecutionListener [org.springframework.boot.test.autoconfigure.SpringBootDependencyInjectionTestExecutionListener@cd3fee8] to prepare test instance [com.nuview.css.webservice.rest.NuCssApiRestServerWebTest@64502326]
java.lang.IllegalStateException: Failed to load ApplicationContext
    at org.springframework.test.context.cache.DefaultCacheAwareContextLoaderDelegate.loadContext(DefaultCacheAwareContextLoaderDelegate.java:124)
    at org.springframework.test.context.support.DefaultTestContext.getApplicationContext(DefaultTestContext.java:83)
    at org.springframework.boot.test.autoconfigure.SpringBootDependencyInjectionTestExecutionListener.prepareTestInstance(SpringBootDependencyInjectionTestExecutionListener.java:47)
    at org.springframework.test.context.TestContextManager.prepareTestInstance(TestContextManager.java:230)
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.createTest(SpringJUnit4ClassRunner.java:228)
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner$1.runReflectiveCall(SpringJUnit4ClassRunner.java:287)
    at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.methodBlock(SpringJUnit4ClassRunner.java:289)
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:247)
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:94)
    at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
    at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
    at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
    at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
    at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
    at org.springframework.test.context.junit4.statements.RunBeforeTestClassCallbacks.evaluate(RunBeforeTestClassCallbacks.java:61)
    at org.springframework.test.context.junit4.statements.RunAfterTestClassCallbacks.evaluate(RunAfterTestClassCallbacks.java:70)
    at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.run(SpringJUnit4ClassRunner.java:191)
    at org.junit.runners.Suite.runChild(Suite.java:128)
    at org.junit.runners.Suite.runChild(Suite.java:27)
    at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
    at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
    at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
    at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
    at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
    at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
    at org.junit.extensions.cpsuite.ClasspathSuite.run(ClasspathSuite.java:196)
    at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:86)
    at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:459)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:678)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:382)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:192)
Caused by: org.yaml.snakeyaml.scanner.ScannerException: while scanning for the next token
found character '@' that cannot start any token. (Do not use @ for indentation)
 in 'reader', line 4, column 21:
        revision:       @buildNumber@
                        ^

    at org.yaml.snakeyaml.scanner.ScannerImpl.fetchMoreTokens(ScannerImpl.java:420)
    at org.yaml.snakeyaml.scanner.ScannerImpl.checkToken(ScannerImpl.java:226)
    at org.yaml.snakeyaml.parser.ParserImpl$ParseBlockMappingValue.produce(ParserImpl.java:585)
    at org.yaml.snakeyaml.parser.ParserImpl.peekEvent(ParserImpl.java:157)
    at org.yaml.snakeyaml.parser.ParserImpl.checkEvent(ParserImpl.java:147)
    at org.yaml.snakeyaml.composer.Composer.composeNode(Composer.java:132)
    at org.yaml.snakeyaml.composer.Composer.composeValueNode(Composer.java:246)
    at org.yaml.snakeyaml.composer.Composer.composeMappingChildren(Composer.java:237)
    at org.yaml.snakeyaml.composer.Composer.composeMappingNode(Composer.java:225)
    at org.yaml.snakeyaml.composer.Composer.composeNode(Composer.java:155)
    at org.yaml.snakeyaml.composer.Composer.composeValueNode(Composer.java:246)
    at org.yaml.snakeyaml.composer.Composer.composeMappingChildren(Composer.java:237)
    at org.yaml.snakeyaml.composer.Composer.composeMappingNode(Composer.java:225)
    at org.yaml.snakeyaml.composer.Composer.composeNode(Composer.java:155)
    at org.yaml.snakeyaml.composer.Composer.composeDocument(Composer.java:122)
    at org.yaml.snakeyaml.composer.Composer.getNode(Composer.java:84)
    at org.yaml.snakeyaml.constructor.BaseConstructor.getData(BaseConstructor.java:104)
    at org.yaml.snakeyaml.Yaml$1.next(Yaml.java:471)
    at org.springframework.beans.factory.config.YamlProcessor.process(YamlProcessor.java:160)
    at org.springframework.beans.factory.config.YamlProcessor.process(YamlProcessor.java:138)
    at org.springframework.boot.env.YamlPropertySourceLoader$Processor.process(YamlPropertySourceLoader.java:101)
    at org.springframework.boot.env.YamlPropertySourceLoader.load(YamlPropertySourceLoader.java:58)
    at org.springframework.boot.env.PropertySourcesLoader.load(PropertySourcesLoader.java:127)
    at org.springframework.boot.context.config.ConfigFileApplicationListener$Loader.loadIntoGroup(ConfigFileApplicationListener.java:472)
    at org.springframework.boot.context.config.ConfigFileApplicationListener$Loader.load(ConfigFileApplicationListener.java:459)
    at org.springframework.boot.context.config.ConfigFileApplicationListener$Loader.load(ConfigFileApplicationListener.java:380)
    at org.springframework.boot.context.config.ConfigFileApplicationListener.addPropertySources(ConfigFileApplicationListener.java:215)
    at org.springframework.boot.context.config.ConfigFileApplicationListener.postProcessEnvironment(ConfigFileApplicationListener.java:184)
    at org.springframework.boot.context.config.ConfigFileApplicationListener.onApplicationEnvironmentPreparedEvent(ConfigFileApplicationListener.java:171)
    at org.springframework.boot.context.config.ConfigFileApplicationListener.onApplicationEvent(ConfigFileApplicationListener.java:157)
    at org.springframework.context.event.SimpleApplicationEventMulticaster.invokeListener(SimpleApplicationEventMulticaster.java:167)
    at org.springframework.context.event.SimpleApplicationEventMulticaster.multicastEvent(SimpleApplicationEventMulticaster.java:139)
    at org.springframework.context.event.SimpleApplicationEventMulticaster.multicastEvent(SimpleApplicationEventMulticaster.java:122)
    at org.springframework.boot.context.event.EventPublishingRunListener.environmentPrepared(EventPublishingRunListener.java:73)
    at org.springframework.boot.SpringApplicationRunListeners.environmentPrepared(SpringApplicationRunListeners.java:54)
    at org.springframework.boot.SpringApplication.prepareEnvironment(SpringApplication.java:336)
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:307)
    at org.springframework.boot.test.context.SpringBootContextLoader.loadContext(SpringBootContextLoader.java:120)
    at org.springframework.test.context.cache.DefaultCacheAwareContextLoaderDelegate.loadContextInternal(DefaultCacheAwareContextLoaderDelegate.java:98)
    at org.springframework.test.context.cache.DefaultCacheAwareContextLoaderDelegate.loadContext(DefaultCacheAwareContextLoaderDelegate.java:116)
    ... 33 common frames omitted

[wilkinsona]

Unfortunately there's nothing we can do about that as it's a limitation of YAML. You could try quoting the build number so that it's treated as a string by the parser.

[ufoscout]

@wilkinsona I agree that this is a limitation of YAML; however, the issue is caused by the fact that spring-boot overrides the default maven delimiter and sets it to the '@' character:

<resource.delimiter>@</resource.delimiter>

Quoting the build number solves the issue if the value is a string; I am not sure if it works in case of, for example, a number.

[wilkinsona]

the issue is caused by the fact that spring-boot overrides the default maven delimiter

You are free to configure the delimiter to something else that meets your needs

Quoting the build number solves the issue if the value is a string; I am not sure if it works in case of, for example, a number.

If you are using @ConfigurationProperties, we'll happily coerce the string into a number. This is exactly what happens when you use a properties file and all the values are strings.

[mejmo]

Please how did you solve this?

[mwalter]

@mejmo I had the same problem. Upgrading to Snakeyaml 1.19 solved the issue for me. I'm using Spring Boot 1.5.10.

[zzclynn]

restarting computer solved my problem... have no clue.

[RadouaneRoufid]

Adding quotes solves it !

info:
  app:
    version: '@project.version@'
    build-date: '@maven.build.timestamp@'

[antonfifindik]

Update intellij idea (to 2018.1.7 (build 181.5540.23)) helped in my case!