Remove ASM dependency and use Spring Core's instead

Depending on ASM itself can cause problems as it can clash with other
libraries' dependency on it. This commit updates
spring-boot-loader-tools to depend upon spring-core and use its
repackaged copy of ASM instead. Depending on spring-core also brings
with it the advantage of giving access to its various bits of utility
code.

spring-boot-maven-plugin has been updated to remove its ASM
exclusions as they will no longer clash with the version from
spring-boot-loader-tools

(59483608)

spring-boot-parent/pom.xml

@@ -163,11 +163,6 @@
 				<artifactId>gradle-plugins</artifactId>
 				<version>${gradle.version}</version>
 			</dependency>
-			<dependency>
-				<groupId>org.ow2.asm</groupId>
-				<artifactId>asm</artifactId>
-				<version>4.1</version>
-			</dependency>
 			<dependency>
 				<groupId>org.zeroturnaround</groupId>
 				<artifactId>zt-zip</artifactId>

spring-boot-tools/spring-boot-loader-tools/pom.xml

@@ -15,8 +15,8 @@
 	<dependencies>
 		<!-- Compile -->
 		<dependency>
-			<groupId>org.ow2.asm</groupId>
-			<artifactId>asm</artifactId>
+			<groupId>org.springframework</groupId>
+			<artifactId>spring-core</artifactId>
 		</dependency>
 		<!-- Provided -->
 		<dependency>

spring-boot-tools/spring-boot-loader-tools/src/main/java/org/springframework/boot/loader/tools/MainClassFinder.java

@@ -33,11 +33,11 @@ import java.util.List;
 import java.util.jar.JarEntry;
 import java.util.jar.JarFile;
 
-import org.objectweb.asm.ClassReader;
-import org.objectweb.asm.ClassVisitor;
-import org.objectweb.asm.MethodVisitor;
-import org.objectweb.asm.Opcodes;
-import org.objectweb.asm.Type;
+import org.springframework.asm.ClassReader;
+import org.springframework.asm.ClassVisitor;
+import org.springframework.asm.MethodVisitor;
+import org.springframework.asm.Opcodes;
+import org.springframework.asm.Type;
 
 /**
  * Finds any class with a {@code public static main} method by performing a breadth first

spring-boot-tools/spring-boot-maven-plugin/pom.xml

@@ -30,12 +30,6 @@
 		<dependency>
 			<groupId>org.apache.maven</groupId>
 			<artifactId>maven-core</artifactId>			
-			<exclusions>
-				<exclusion>
-					<groupId>asm</groupId>
-					<artifactId>asm</artifactId>
-				</exclusion>
-			</exclusions>
 		</dependency>
 		<dependency>
 			<groupId>org.apache.maven</groupId>
@@ -67,37 +61,11 @@
 			<groupId>org.codehaus.plexus</groupId>
 			<artifactId>plexus-utils</artifactId>
 		</dependency>
-		<dependency>
-			<groupId>org.ow2.asm</groupId>
-			<artifactId>asm</artifactId>
-		</dependency>
 		<!-- Optional -->
 		<dependency>
 			<groupId>org.apache.maven.plugins</groupId>
 			<artifactId>maven-shade-plugin</artifactId>
 			<optional>true</optional>			
-			<exclusions>
-				<exclusion>
-					<groupId>asm</groupId>
-					<artifactId>asm</artifactId>
-				</exclusion>
-				<exclusion>
-					<groupId>asm</groupId>
-					<artifactId>asm-analysis</artifactId>
-				</exclusion>
-				<exclusion>
-					<groupId>asm</groupId>
-					<artifactId>asm-commons</artifactId>
-				</exclusion>
-				<exclusion>
-					<groupId>asm</groupId>
-					<artifactId>asm-tree</artifactId>
-				</exclusion>
-				<exclusion>
-					<groupId>asm</groupId>
-					<artifactId>asm-util</artifactId>
-				</exclusion>
-			</exclusions>
 		</dependency>
 		<!-- Provided -->
 		<dependency>