Protect against malformed logging.config

Ensure that any user specified logging.config exists. Required for
CI build as bamboo sets a "LOGGING_CONFIG" environment variable.

spring-bootstrap/src/main/java/org/springframework/bootstrap/context/initializer/LoggingApplicationContextInitializer.java

@@ -20,6 +20,8 @@ import java.lang.management.ManagementFactory;
 import java.util.HashMap;
 import java.util.Map;
 
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
 import org.springframework.bootstrap.logging.JavaLoggerConfigurer;
 import org.springframework.bootstrap.logging.LogbackConfigurer;
 import org.springframework.context.ApplicationContext;
@@ -31,6 +33,7 @@ import org.springframework.core.env.Environment;
 import org.springframework.core.io.ClassPathResource;
 import org.springframework.util.ClassUtils;
 import org.springframework.util.Log4jConfigurer;
+import org.springframework.util.ResourceUtils;
 
 /**
  * An {@link ApplicationContextInitializer} that configures a logging framework depending
@@ -157,6 +160,9 @@ public class LoggingApplicationContextInitializer implements
 			}
 		};
 
+		private final Log logger = LogFactory
+				.getLog(LoggingApplicationContextInitializer.class);
+
 		private final String className;
 
 		private final String[] paths;
@@ -186,7 +192,16 @@ public class LoggingApplicationContextInitializer implements
 
 			// User specified config
 			if (environment.containsProperty("logging.config")) {
-				return environment.getProperty("logging.config");
+				String value = environment.getProperty("logging.config");
+				try {
+					ResourceUtils.getURL(value).openStream().close();
+					return value;
+				}
+				catch (Exception ex) {
+					// Swallow exception and continue
+				}
+				this.logger.warn("Logging environment value '" + value
+						+ "' cannot be opened and will be ignored");
 			}
 
 			// Common patterns

spring-bootstrap/src/test/java/org/springframework/bootstrap/logging/LoggingApplicationContextInitializerTests.java

@@ -104,6 +104,23 @@ public class LoggingApplicationContextInitializerTests {
 		assertTrue("Wrong output:\n" + output, output.startsWith("/tmp/spring.log"));
 	}
 
+	@Test
+	public void testOverrideConfigDoesNotExist() throws Exception {
+		GenericApplicationContext context = new GenericApplicationContext();
+		context.getEnvironment().getPropertySources()
+				.addFirst(new PropertySource<String>("manual") {
+					@Override
+					public Object getProperty(String name) {
+						if ("logging.config".equals(name)) {
+							return "doesnotexist.xml";
+						}
+						return null;
+					}
+				});
+		this.initializer.initialize(context);
+		// Should not throw
+	}
+
 	@Test
 	public void testAddLogFileProperty() {
 		GenericApplicationContext context = new GenericApplicationContext();