Improve exception messages to properly include specified sources

Closes gh-4687

spring-boot-cli/src/main/java/org/springframework/boot/cli/command/run/SpringApplicationRunner.java

@@ -22,6 +22,7 @@ import java.lang.reflect.Method;
 import java.net.MalformedURLException;
 import java.net.URL;
 import java.util.ArrayList;
+import java.util.Arrays;
 import java.util.List;
 import java.util.concurrent.TimeUnit;
 import java.util.logging.Level;
@@ -117,7 +118,8 @@ public class SpringApplicationRunner {
 	private Object[] compile() throws IOException {
 		Object[] compiledSources = this.compiler.compile(this.sources);
 		if (compiledSources.length == 0) {
-			throw new RuntimeException("No classes found in '" + this.sources + "'");
+			throw new RuntimeException(
+					"No classes found in '" + Arrays.toString(this.sources) + "'");
 		}
 		return compiledSources;
 	}

spring-boot-cli/src/main/java/org/springframework/boot/cli/command/test/TestRunner.java

@@ -19,6 +19,7 @@ package org.springframework.boot.cli.command.test;
 import java.lang.annotation.Annotation;
 import java.lang.reflect.Method;
 import java.util.ArrayList;
+import java.util.Arrays;
 import java.util.List;
 
 import org.springframework.boot.cli.compiler.GroovyCompiler;
@@ -55,7 +56,8 @@ public class TestRunner {
 	public void compileAndRunTests() throws Exception {
 		Object[] sources = this.compiler.compile(this.sources);
 		if (sources.length == 0) {
-			throw new RuntimeException("No classes found in '" + this.sources + "'");
+			throw new RuntimeException(
+					"No classes found in '" + Arrays.toString(this.sources) + "'");
 		}
 
 		// Run in new thread to ensure that the context classloader is setup