Relax requirement for groovy template directory to exist

Since groovy-templates is included with groovy-all it is unreasonable
to expect anyone who has it on their classpath to have resolvable templates.
We may need to revisit this decision, but since the origain feature
that drove this was thymeleaf and idaiotic users having it on their
classpath but not using it, maybe we don't need to.

spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/groovy/template/GroovyTemplateAutoConfiguration.java

@@ -24,7 +24,6 @@ import groovy.text.markup.TemplateConfiguration;
 import java.net.URL;
 import java.net.URLClassLoader;
 
-import javax.annotation.PostConstruct;
 import javax.servlet.Servlet;
 
 import org.springframework.beans.factory.BeanClassLoaderAware;
@@ -44,7 +43,6 @@ import org.springframework.core.Ordered;
 import org.springframework.core.io.DefaultResourceLoader;
 import org.springframework.core.io.Resource;
 import org.springframework.core.io.ResourceLoader;
-import org.springframework.util.Assert;
 
 /**
  * Autoconfiguration support for Groovy templates in MVC. By default creates a
@@ -66,17 +64,6 @@ public class GroovyTemplateAutoConfiguration {
 	@Autowired
 	private GroovyTemplateProperties properties;
 
-	@PostConstruct
-	public void checkTemplateLocationExists() {
-		if (this.properties.isCheckTemplateLocation()) {
-			Resource resource = this.resourceLoader.getResource(this.properties
-					.getPrefix());
-			Assert.state(resource.exists(), "Cannot find template location: " + resource
-					+ " (please add some templates "
-					+ "or check your FreeMarker configuration)");
-		}
-	}
-
 	@Configuration
 	@ConditionalOnClass({ Servlet.class, LocaleContextHolder.class })
 	@ConditionalOnWebApplication
@@ -108,8 +95,15 @@ public class GroovyTemplateAutoConfiguration {
 		}
 
 		private ClassLoader createParentLoaderForTemplates() throws Exception {
-			return new URLClassLoader(new URL[] { this.resourceLoader.getResource(
-					this.properties.getPrefix()).getURL() }, this.classLoader);
+			Resource resource = this.resourceLoader.getResource(this.properties
+					.getPrefix());
+			if (resource.exists()) {
+				return new URLClassLoader(new URL[] { resource.getURL() },
+						this.classLoader);
+			}
+			else {
+				return this.classLoader;
+			}
 		}
 
 		@Bean

spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/groovy/template/GroovyTemplateProperties.java

@@ -43,7 +43,7 @@ public class GroovyTemplateProperties {
 
 	private String[] viewNames;
 
-	private boolean checkTemplateLocation = true;
+	private boolean checkTemplateLocation = false;
 
 	private TemplateConfiguration configuration = new TemplateConfiguration();
 

spring-boot-autoconfigure/src/main/resources/META-INF/spring.factories

@@ -44,5 +44,6 @@ org.springframework.boot.autoconfigure.websocket.WebSocketAutoConfiguration
 # Template availability providers
 org.springframework.boot.autoconfigure.template.TemplateAvailabilityProvider=\
 org.springframework.boot.autoconfigure.freemarker.FreeMarkerTemplateAvailabilityProvider,\
+org.springframework.boot.autoconfigure.groovy.template.GroovyTemplateAvailabilityProvider,\
 org.springframework.boot.autoconfigure.thymeleaf.ThymeleafTemplateAvailabilityProvider,\
 org.springframework.boot.autoconfigure.web.JspTemplateAvailabilityProvider

spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/groovy/template/GroovyTemplateAutoConfigurationTests.java

@@ -30,7 +30,6 @@ import javax.servlet.http.HttpServletRequest;
 import org.junit.After;
 import org.junit.Before;
 import org.junit.Test;
-import org.springframework.beans.factory.BeanCreationException;
 import org.springframework.boot.autoconfigure.groovy.template.web.GroovyTemplateViewResolver;
 import org.springframework.boot.test.EnvironmentTestUtils;
 import org.springframework.context.i18n.LocaleContextHolder;
@@ -75,12 +74,6 @@ public class GroovyTemplateAutoConfigurationTests {
 		assertThat(this.context.getBean(GroovyTemplateViewResolver.class), notNullValue());
 	}
 
-	@Test(expected = BeanCreationException.class)
-	public void nonExistentTemplateLocation() {
-		registerAndRefreshContext("spring.groovy.template.prefix:"
-				+ "classpath:/does-not-exist/");
-	}
-
 	@Test
 	public void emptyTemplateLocation() {
 		new File("target/test-classes/templates/empty-directory").mkdir();