added advanced Spring Retry example and removed Spring Retry xml config

spring-scheduling/src/main/java/com/baeldung/springretry/MyService.java

@@ -2,18 +2,27 @@ package com.baeldung.springretry;
 
 import java.sql.SQLException;
 
+import org.springframework.context.annotation.PropertySource;
 import org.springframework.retry.annotation.Backoff;
 import org.springframework.retry.annotation.Recover;
 import org.springframework.retry.annotation.Retryable;
 
+
 public interface MyService {
 
     @Retryable
     void retryService();
 
-    @Retryable(value = { SQLException.class }, maxAttempts = 2, backoff = @Backoff(delay = 5000))
+    @Retryable(value = SQLException.class)
     void retryServiceWithRecovery(String sql) throws SQLException;
 
+    @Retryable(value = { SQLException.class }, maxAttempts = 2, backoff = @Backoff(delay = 100))
+    void retryServiceWithCustomization(String sql) throws SQLException;
+
+    @Retryable( value = SQLException.class, maxAttemptsExpression = "${retry.maxAttempts}",
+                        backoff = @Backoff(delayExpression = "${retry.maxDelay}"))
+    void retryServiceWithExternalConfiguration(String sql) throws SQLException;
+
     @Recover
     void recover(SQLException e, String sql);