Troubleshooting Common Issues in Spring Projects. Spring Framework

Project Description

The Spring Framework is an open-source application framework and inversion of a control container for the Java platform. The framework’s core features can be used by any Java application, but there are extensions for building web applications on top of the Java EE (Enterprise Edition) platform.

The Spring Framework provides a comprehensive programming and configuration model for modern Java-based enterprise applications – on any kind of deployment platform. A key element of Spring is infrastructural support at the application level: Spring focuses on the “plumbing” of enterprise applications so that teams can focus on application-level business logic, without unnecessary ties to specific deployment environments.

The Spring Framework provides a range of features that enable you to build high-quality applications.

Troubleshooting Spring Projects-Spring Framework with the Lightrun Developer Observability Platform

Add @FormAttribute attributes to customize x-www-form-urlencoded [SPR-13433]

Having wrestled with the complexities of having varying formats for both query parameters and form data compared to their respective @ModelAttribute property names, Spring-oriented approach was developed which may be beneficial to others. View an attempt at addressing this problem on GitHub: https://github.com/mattbertolini/spring-annotated-web-data binder

Inherited @Transactional methods use wrong TransactionManager

After a long-term effort, it managed to overcome the difficulty without any requirement for patching the spring-tx library; thus eliminating the need of creating patches every time a new version of Spring is released.

The default “transactionAttributeSource” bean (defined in ProxyTransactionManagementConfiguration) will be replaced (1) by an instance of the own MergeAnnotationTransactionAttributeSource (2).

(1) AnnotationTransactionAttributeSourceReplacer

The implementation of the PriorityOrdered interface in the replacer was essential. If this step had not been taken, it would have caused a delay when creating the “transactionAttributeSource” bean as seen in PostProcessorRegistrationDelegate#invokeBeanFactoryPostProcessors. Although an Ordered Interface may also suffice for this purpose, PriorityOrderer is more suited to achieve desired results promptly.

import org.springframework.beans.BeansException;
import org.springframework.beans.factory.config.InstantiationAwareBeanPostProcessor;
import org.springframework.core.PriorityOrdered;
import org.springframework.stereotype.Component;
import org.springframework.transaction.annotation.ProxyTransactionManagementConfiguration;
import org.springframework.transaction.interceptor.TransactionAttributeSource;

import lombok.extern.slf4j.Slf4j;

/**
 * Replaces the default "transactionAttributeSource" bean (defined in {@link ProxyTransactionManagementConfiguration}) 
 * with instance of {@link MergeAnnotationTransactionAttributeSource}.
 *
 * @author Eugen Labun
 */
@Slf4j
@Component
public class AnnotationTransactionAttributeSourceReplacer implements InstantiationAwareBeanPostProcessor, PriorityOrdered /*this is important*/ {

    public AnnotationTransactionAttributeSourceReplacer() {
        // to check that the replacer is created before instantiation of the "transactionAttributeSource" bean
        log.trace("AnnotationTransactionAttributeSourceReplacer - constructor");
    }

    @Override
    public Object postProcessBeforeInstantiation(Class<?> beanClass, String beanName) throws BeansException {
        // log.trace("postProcessBeforeInstantiation - beanName: {}, beanClass: {}", beanName, beanClass);
        if (beanName.equals("transactionAttributeSource") && TransactionAttributeSource.class.isAssignableFrom(beanClass)) {
            log.debug("instantiating bean {} as {}", beanName, MergeAnnotationTransactionAttributeSource.class.getName());
            return new MergeAnnotationTransactionAttributeSource();
        } else {
            return null;
        }
    }

    @Override
    public int getOrder() {
        return 0;
    }
}

(2) MergeAnnotationTransactionAttributeSource

import java.lang.reflect.Method;
import java.lang.reflect.Modifier;

import org.springframework.aop.support.AopUtils;
import org.springframework.lang.Nullable;
import org.springframework.transaction.TransactionDefinition;
import org.springframework.transaction.annotation.AnnotationTransactionAttributeSource;
import org.springframework.transaction.annotation.Transactional;
import org.springframework.transaction.interceptor.AbstractFallbackTransactionAttributeSource;
import org.springframework.transaction.interceptor.DefaultTransactionAttribute;
import org.springframework.transaction.interceptor.RuleBasedTransactionAttribute;
import org.springframework.transaction.interceptor.TransactionAttribute;
import org.springframework.util.ClassUtils;

import lombok.extern.slf4j.Slf4j;

/**
 * Implements a merge policy for transaction attributes (see {@link Transactional} annotation)
 * with following priorities (high to low):
 * <ol>
 * <li>specific method;
 * <li>declaring class of the specific method;
 * <li>target class;
 * <li>method in the declaring class/interface;
 * <li>declaring class/interface.
 * </ol>
 *
 * <p>The merge policy means that all transaction attributes which are not
 * explicitly set [1] on a specific definition place (see above) will be inherited
 * from the place with the next lower priority.
 * 
 * <p>On the contrary, the Spring default {@link AbstractFallbackTransactionAttributeSource} implements a fallback policy, 
 * where all attributes are read from the first found definition place (essentially in the above order), and all others are ignored.
 * 
 * <p>See analysis in <a href="https://github.com/spring-projects/spring-framework/issues/24291">Inherited @Transactional methods use wrong TransactionManager</a>.
 * 
 * <p>[1] If the value of an attribute is equal to its default value, the current implementation 
 * cannot distinguish, whether this value has been set explicitly or implicitly, 
 * and considers such attribute as "not explicitly set". Therefore it's currently impossible to override a non-default value with a default value.
 *
 * @author Eugen Labun
 */
@Slf4j
@SuppressWarnings("serial")
public class MergeAnnotationTransactionAttributeSource extends AnnotationTransactionAttributeSource {

    public MergeAnnotationTransactionAttributeSource() {
        log.info("MergeAnnotationTransactionAttributeSource constructor");
    }

    @Override
    @Nullable
    protected TransactionAttribute computeTransactionAttribute(Method method, @Nullable Class<?> targetClass) {
        // Don't allow no-public methods as required.
        if (allowPublicMethodsOnly() && !Modifier.isPublic(method.getModifiers())) {
            return null;
        }

        // The method may be on an interface, but we also need attributes from the target class.
        // If the target class is null, the method will be unchanged.
        Method specificMethod = AopUtils.getMostSpecificMethod(method, targetClass);

        // 1st priority is the specific method.
        TransactionAttribute txAttr = findTransactionAttribute(specificMethod);

        // 2nd priority is the declaring class of the specific method.
        Class<?> declaringClass = specificMethod.getDeclaringClass();
        boolean userLevelMethod = ClassUtils.isUserLevelMethod(method);
        if (userLevelMethod) {
            txAttr = merge(txAttr, findTransactionAttribute(declaringClass));
        }

        // 3rd priority is the target class
        if (targetClass != null && !targetClass.equals(declaringClass) && userLevelMethod) {
            txAttr = merge(txAttr, findTransactionAttribute(targetClass));
        }

        if (method != specificMethod) {
            // 4th priority is the method in the declaring class/interface.
            txAttr = merge(txAttr, findTransactionAttribute(method));

            // 5th priority is the declaring class/interface.
            txAttr = merge(txAttr, findTransactionAttribute(method.getDeclaringClass()));
        }

        return txAttr;
    }

    /**
     * Set empty and default properties of "primary" object from "secondary" object.
     * <p>Parameter objects should not be used after the call to this method,
     * as they can be changed here or/and returned as a result.
     */
    @Nullable
    private TransactionAttribute merge(@Nullable TransactionAttribute primaryObj, @Nullable TransactionAttribute secondaryObj) {
        if (primaryObj == null) {
            return secondaryObj;
        }
        if (secondaryObj == null) {
            return primaryObj;
        }

        if (primaryObj instanceof DefaultTransactionAttribute && secondaryObj instanceof DefaultTransactionAttribute) {
            DefaultTransactionAttribute primary = (DefaultTransactionAttribute) primaryObj;
            DefaultTransactionAttribute secondary = (DefaultTransactionAttribute) secondaryObj;

            if (primary.getQualifier() == null || primary.getQualifier().isEmpty()) {
                primary.setQualifier(secondary.getQualifier());
            }
            if (primary.getDescriptor() == null || primary.getDescriptor().isEmpty()) {
                primary.setDescriptor(secondary.getDescriptor());
            }
            if (primary.getName() == null || primary.getName().isEmpty()) {
                primary.setName(secondary.getName());
            }

            // The following properties have default values in DefaultTransactionDefinition;
            // we cannot distinguish here, whether these values have been set explicitly or implicitly;
            // but it seems to be logical to handle default values like empty values.
            if (primary.getPropagationBehavior() == TransactionDefinition.PROPAGATION_REQUIRED) {
                primary.setPropagationBehavior(secondary.getPropagationBehavior());
            }
            if (primary.getIsolationLevel() == TransactionDefinition.ISOLATION_DEFAULT) {
                primary.setIsolationLevel(secondary.getIsolationLevel());
            }
            if (primary.getTimeout() == TransactionDefinition.TIMEOUT_DEFAULT) {
                primary.setTimeout(secondary.getTimeout());
            }
            if (!primary.isReadOnly()) {
                primary.setReadOnly(secondary.isReadOnly());
            }
        }

        if (primaryObj instanceof RuleBasedTransactionAttribute && secondaryObj instanceof RuleBasedTransactionAttribute) {
            RuleBasedTransactionAttribute primary = (RuleBasedTransactionAttribute) primaryObj;
            RuleBasedTransactionAttribute secondary = (RuleBasedTransactionAttribute) secondaryObj;

            if (primary.getRollbackRules() == null || primary.getRollbackRules().isEmpty()) {
                primary.setRollbackRules(secondary.getRollbackRules());
            }
        }

        return primaryObj;
    }

}

Support for form data via @RequestParam on WebFlux [SPR-16190]

For posterity, a workaround has been achieved. An impeccably crafted FormDataWorkaround java file is now available for use.

Converters annotated with @Converter cannot be autowired into

Struggling with a seemingly similar issue? It can be easily solved by utilizing the SpringBeanContainer.

LocalContainerEntityManagerFactoryBean emfb = ...
emfb.getJpaPropertyMap().put(AvailableSettings.BEAN_CONTAINER, new 
SpringBeanContainer(beanFactory));

More issues from Spring Projects repos

Troubleshooting spring projects-spring boot | Troubleshooting-spring-projects-spring-data-jpa | Troubleshooting-spring-projects-spring-data-rest | Troubleshooting-spring-projects-spring-security