Port GroovyDynamicElementReader to Java

Prior to this commit, GroovyDynamicElementReader was implemented in
Groovy, which required that developers have Groovy language support
installed and configured in their IDEs.

This commit ports GroovyDynamicElementReader from Groovy to Java,
making the compilation much simpler and allowing developers to open the
project in Eclipse or VSCode (or other IDEs without Groovy support)
without compiler errors.

This commit also converts related tests from Groovy to Java.

Closes gh-27945

spring-context/src/test/java/org/springframework/context/groovy/GroovyApplicationContextDynamicBeanPropertyTests.java

@@ -14,14 +14,16 @@
  * limitations under the License.
  */
 
-package org.springframework.context.groovy
+package org.springframework.context.groovy;
 
-import org.junit.jupiter.api.Test
+import org.junit.jupiter.api.Test;
 
-import org.springframework.beans.factory.NoSuchBeanDefinitionException
-import org.springframework.context.support.GenericGroovyApplicationContext
+import org.springframework.beans.factory.NoSuchBeanDefinitionException;
+import org.springframework.context.support.GenericGroovyApplicationContext;
 
-import static groovy.test.GroovyAssert.*
+import static groovy.test.GroovyAssert.assertEquals;
+import static groovy.test.GroovyAssert.assertNotNull;
+import static groovy.test.GroovyAssert.assertThrows;
 
 /**
  * @author Jeff Brown
@@ -31,24 +33,26 @@ class GroovyApplicationContextDynamicBeanPropertyTests {
 
 	@Test
 	void testAccessDynamicBeanProperties() {
-		def ctx = new GenericGroovyApplicationContext();
-		ctx.reader.loadBeanDefinitions("org/springframework/context/groovy/applicationContext.groovy");
-		ctx.refresh()
+		var ctx = new GenericGroovyApplicationContext();
+		ctx.getReader().loadBeanDefinitions("org/springframework/context/groovy/applicationContext.groovy");
+		ctx.refresh();
 
-		def framework = ctx.framework
-		assertNotNull 'could not find framework bean', framework
-		assertEquals 'Grails', framework
+		var framework = ctx.getProperty("framework");
+		assertNotNull("could not find framework bean", framework);
+		assertEquals("Grails", framework);
+		ctx.close();
 	}
 
 	@Test
 	void testAccessingNonExistentBeanViaDynamicProperty() {
-		def ctx = new GenericGroovyApplicationContext();
-		ctx.reader.loadBeanDefinitions("org/springframework/context/groovy/applicationContext.groovy");
-		ctx.refresh()
+		var ctx = new GenericGroovyApplicationContext();
+		ctx.getReader().loadBeanDefinitions("org/springframework/context/groovy/applicationContext.groovy");
+		ctx.refresh();
 
-		def err = shouldFail NoSuchBeanDefinitionException, { ctx.someNonExistentBean }
+		var err = assertThrows(NoSuchBeanDefinitionException.class, () -> ctx.getProperty("someNonExistentBean"));
 
-		assertEquals "No bean named 'someNonExistentBean' available", err.message
+		assertEquals("No bean named 'someNonExistentBean' available", err.getMessage());
+		ctx.close();
 	}
 
 }