Instruction:
作为 Java 安全专家，检测此代码中的安全漏洞：
## 内容1
### 文件路径：
ambari-server/src/main/java/org/apache/ambari/server/agent/stomp/AmbariSubscriptionRegistry.java
### 代码内容：
/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.ambari.server.agent.stomp;

import java.util.Collection;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;
import java.util.concurrent.CopyOnWriteArraySet;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.expression.AccessException;
import org.springframework.expression.EvaluationContext;
import org.springframework.expression.Expression;
import org.springframework.expression.ExpressionParser;
import org.springframework.expression.PropertyAccessor;
import org.springframework.expression.TypedValue;
import org.springframework.expression.spel.SpelEvaluationException;
import org.springframework.expression.spel.standard.SpelExpressionParser;
import org.springframework.expression.spel.support.StandardEvaluationContext;
import org.springframework.messaging.Message;
import org.springframework.messaging.MessageHeaders;
import org.springframework.messaging.simp.SimpMessageHeaderAccessor;
import org.springframework.messaging.simp.broker.AbstractSubscriptionRegistry;
import org.springframework.messaging.simp.broker.SubscriptionRegistry;
import org.springframework.messaging.support.MessageHeaderAccessor;
import org.springframework.util.AntPathMatcher;
import org.springframework.util.Assert;
import org.springframework.util.LinkedMultiValueMap;
import org.springframework.util.MultiValueMap;
import org.springframework.util.PathMatcher;

import com.google.common.cache.Cache;
import com.google.common.cache.CacheBuilder;

/**
 * Implementation of {@link SubscriptionRegistry} that has configurable cache size, optimized working with cache and
 * destinations matching.
 */
public class AmbariSubscriptionRegistry extends AbstractSubscriptionRegistry {
  private static final Logger LOG = LoggerFactory.getLogger(AmbariSubscriptionRegistry.class);

  private PathMatcher pathMatcher = new AntPathMatcher();

  private volatile int cacheLimit;

  private String selectorHeaderName = "selector";

  private volatile boolean selectorHeaderInUse = false;

  private final ExpressionParser expressionParser = new SpelExpressionParser();

  private final DestinationCache destinationCache;

  private final SessionSubscriptionRegistry subscriptionRegistry = new SessionSubscriptionRegistry();

  public AmbariSubscriptionRegistry(int cacheLimit) {
    this.cacheLimit = cacheLimit;
    destinationCache = new DestinationCache();
  }

  /**
   * Specify the {@link PathMatcher} to use.
   */
  public void setPathMatcher(PathMatcher pathMatcher) {
    this.pathMatcher = pathMatcher;
  }

  /**
   * Return the configured {@link PathMatcher}.
   */
  public PathMatcher getPathMatcher() {
    return this.pathMatcher;
  }

  /**
   * Specify the maximum number of entries for the resolved destination cache.
   * Default is 1024.
   */
  public void setCacheLimit(int cacheLimit) {
    this.cacheLimit = cacheLimit;
  }

  /**
   * Return the maximum number of entries for the resolved destination cache.
   */
  public int getCacheLimit() {
    return this.cacheLimit;
  }

  /**
   * Configure the name of a selector header that a subscription message can
   * have in order to filter messages based on their headers. The value of the
   * header can use Spring EL expressions against message headers.
   *
For example the following expression expects a header called "foo" to
   * have the value "bar":
   *

   * headers.foo == 'bar'
   *

   *
By default this is set to "selector".
   * @since 4.2
   */
  public void setSelectorHeaderName(String selectorHeaderName) {
    Assert.notNull(selectorHeaderName, "'selectorHeaderName' must not be null");
    this.selectorHeaderName = selectorHeaderName;
  }

  /**
   * Return the name for the selector header.
   * @since 4.2
   */
  public String getSelectorHeaderName() {
    return this.selectorHeaderName;
  }

  @Override
  protected void addSubscriptionInternal(
      String sessionId, String subsId, String destination, Message<?> message) {

    Expression expression = null;
    MessageHeaders headers = message.getHeaders();
    String selector = SimpMessageHeaderAccessor.getFirstNativeHeader(getSelectorHeaderName(), headers);
    if (selector != null) {
      try {
        expression = this.expressionParser.parseExpression(selector);
        this.selectorHeaderInUse = true;
        if (logger.isTraceEnabled()) {
          logger.trace("Subscription selector: [" + selector + "]");
        }
      }
      catch (Throwable ex) {
        if (logger.isDebugEnabled()) {
          logger.debug("Failed to parse selector: " + selector, ex);
        }
      }
    }
    this.subscriptionRegistry.addSubscription(sessionId, subsId, destination, expression);
    this.destinationCache.updateAfterNewSubscription(destination, sessionId, subsId);
  }

  @Override
  protected void removeSubscriptionInternal(String sessionId, String subsId, Message<?> message) {
    SessionSubscriptionInfo info = this.subscriptionRegistry.getSubscriptions(sessionId);
    if (info != null) {
      String destination = info.removeSubscription(subsId);
      if (destination != null) {
        this.destinationCache.updateAfterRemovedSubscription(sessionId, subsId);
      }
    }
  }

  @Override
  public void unregisterAllSubscriptions(String sessionId) {
    SessionSubscriptionInfo info = this.subscriptionRegistry.removeSubscriptions(sessionId);
    if (info != null) {
      this.destinationCache.updateAfterRemovedSession(info);
    }
  }

  @Override
  protected MultiValueMap<String, String> findSubscriptionsInternal(String destination, Message<?> message) {
    MultiValueMap<String, String> result = this.destinationCache.getSubscriptions(destination, message);
    return filterSubscriptions(result, message);
  }

  private MultiValueMap<String, String> filterSubscriptions(
      MultiValueMap<String, String> allMatches, Message<?> message) {

    if (!this.selectorHeaderInUse) {
      return allMatches;
    }
    EvaluationContext context = null;
    MultiValueMap<String, String> result = new LinkedMultiValueMap<String, String>(allMatches.size());
    for (String sessionId : allMatches.keySet()) {
      for (String subId : allMatches.get(sessionId)) {
        SessionSubscriptionInfo info = this.subscriptionRegistry.getSubscriptions(sessionId);
        if (info == null) {
          continue;
        }
        Subscription sub = info.getSubscription(subId);
        if (sub == null) {
          continue;
        }
        Expression expression = sub.getSelectorExpression();
        if (expression == null) {
          result.add(sessionId, subId);
          continue;
        }
        if (context == null) {
          context = new StandardEvaluationContext(message);
          context.getPropertyAccessors().add(new SimpMessageHeaderPropertyAccessor());
        }
        try {
          if (expression.getValue(context, boolean.class)) {
            result.add(sessionId, subId);
          }
        }
        catch (SpelEvaluationException ex) {
          if (logger.isDebugEnabled()) {
            logger.debug("Failed to evaluate selector: " + ex.getMessage());
          }
        }
        catch (Throwable ex) {
          logger.debug("Failed to evaluate selector", ex);
        }
      }
    }
    return result;
  }

  @Override
  public String toString() {
    return "DefaultSubscriptionRegistry[" + this.destinationCache + ", " + this.subscriptionRegistry + "]";
  }

  /**
   * A cache for destinations previously resolved via
   * {@link org.springframework.messaging.simp.broker.DefaultSubscriptionRegistry#findSubscriptionsInternal(String, Message)}
   */
  private class DestinationCache {

    /** Map from destination -> <sessionId, subscriptionId> for fast look-ups */
    private final Map<String, LinkedMultiValueMap<String, String>> accessCache =
        new ConcurrentHashMap<>(cacheLimit);

    //TODO optimize usage of this cache on perf cluster
    private final Cache<String, String> notSubscriptionCache =
        CacheBuilder.newBuilder().maximumSize(cacheLimit).build();

    public LinkedMultiValueMap<String, String> getSubscriptions(String destination, Message<?> message) {
      if (notSubscriptionCache.asMap().keySet().contains(destination)) {
        return new LinkedMultiValueMap<>();
      }
      LinkedMultiValueMap<String, String> subscriptions = this.accessCache.computeIfAbsent(destination, (key) -> {
        LinkedMultiValueMap<String, String> result = new LinkedMultiValueMap<>();
        for (SessionSubscriptionInfo info : subscriptionRegistry.getAllSubscriptions()) {
          for (String destinationPattern : info.getDestinations()) {
            //TODO temporary changed to more fast-acting check without regex, need move investigation
            if (destinationPattern.equals(destination)) {
              for (Subscription subscription : info.getSubscriptions(destinationPattern)) {
                result.add(info.sessionId, subscription.getId());
              }
            }
          }
        }
        if (!result.isEmpty()) {
          return result;
        } else {
          notSubscriptionCache.put(destination, "");
          return null;
        }
      });
      return subscriptions == null ? new LinkedMultiValueMap<>() : subscriptions;
    }

    public void updateAfterNewSubscription(String destination, String sessionId, String subsId) {
      LinkedMultiValueMap<String, String> updatedMap = this.accessCache.computeIfPresent(destination, (key, value) -> {
        if (getPathMatcher().match(destination, key)) {
          LinkedMultiValueMap<String, String> subs = value.deepCopy();
          subs.add(sessionId, subsId);
          return subs;
        }
        return value;
      });
      if (updatedMap == null) {
        this.notSubscriptionCache.invalidate(destination);
      }
    }

    public void updateAfterRemovedSubscription(String sessionId, String subsId) {
      for (Iterator<Map.Entry<String, LinkedMultiValueMap<String, String>>> iterator =
           this.accessCache.entrySet().iterator(); iterator.hasNext(); ) {
        Map.Entry<String, LinkedMultiValueMap<String, String>> entry = iterator.next();
        String destination = entry.getKey();
        accessCache.computeIfPresent(destination, (key, sessionMap)-> {
          List<String> subscriptions = sessionMap.get(sessionId);
          if (subscriptions != null) {
            subscriptions.remove(subsId);
            if (subscriptions.isEmpty()) {
              sessionMap.remove(sessionId);
            }
            if (sessionMap.isEmpty()) {
              return null;
            }
            else {
              this.notSubscriptionCache.invalidate(destination);
              return sessionMap.deepCopy();
            }
          }
          return sessionMap;
        });
      }
    }

    public void updateAfterRemovedSession(SessionSubscriptionInfo info) {
      for (Iterator<Map.Entry<String, LinkedMultiValueMap<String, String>>> iterator =
           this.accessCache.entrySet().iterator(); iterator.hasNext(); ) {
        Map.Entry<String, LinkedMultiValueMap<String, String>> entry = iterator.next();
        String destination = entry.getKey();
        accessCache.computeIfPresent(destination, (key, sessionMap)-> {
          if (sessionMap.remove(info.getSessionId()) != null) {
            if (sessionMap.isEmpty()) {
              return null;
            }
            else {
              this.notSubscriptionCache.invalidate(destination);
              return sessionMap.deepCopy();
            }
          }
          return sessionMap;
        });
      }
    }

    @Override
    public String toString() {
      return "cache[" + this.accessCache.size() + " destination(s)]";
    }
  }

  /**
   * Provide access to session subscriptions by sessionId.
   */
  private static class SessionSubscriptionRegistry {

    // sessionId -> SessionSubscriptionInfo
    private final ConcurrentMap<String, SessionSubscriptionInfo> sessions =
        new ConcurrentHashMap<String, SessionSubscriptionInfo>();

    public SessionSubscriptionInfo getSubscriptions(String sessionId) {
      return this.sessions.get(sessionId);
    }

    public Collection<SessionSubscriptionInfo> getAllSubscriptions() {
      return this.sessions.values();
    }

    public SessionSubscriptionInfo addSubscription(String sessionId, String subscriptionId,
                                                                                String destination, Expression selectorExpression) {

      SessionSubscriptionInfo info = this.sessions.get(sessionId);
      if (info == null) {
        info = new SessionSubscriptionInfo(sessionId);
        SessionSubscriptionInfo value = this.sessions.putIfAbsent(sessionId, info);
        if (value != null) {
          info = value;
        }
      }
      info.addSubscription(destination, subscriptionId, selectorExpression);
      return info;
    }

    public SessionSubscriptionInfo removeSubscriptions(String sessionId) {
      return this.sessions.remove(sessionId);
    }

    @Override
    public String toString() {
      return "registry[" + this.sessions.size() + " sessions]";
    }
  }

  /**
   * Hold subscriptions for a session.
   */
  private static class SessionSubscriptionInfo {

    private final String sessionId;

    // destination -> subscriptions
    private final Map<String, Set<Subscription>> destinationLookup =
        new ConcurrentHashMap<String, Set<Subscription>>(4);

    public SessionSubscriptionInfo(String sessionId) {
      Assert.notNull(sessionId, "'sessionId' must not be null");
      this.sessionId = sessionId;
    }

    public String getSessionId() {
      return this.sessionId;
    }

    public Set<String> getDestinations() {
      return this.destinationLookup.keySet();
    }

    public Set<Subscription> getSubscriptions(String destination) {
      return this.destinationLookup.get(destination);
    }

    public Subscription getSubscription(String subscriptionId) {
      for (String destination : this.destinationLookup.keySet()) {
        Set<Subscription> subs = this.destinationLookup.get(destination);
        if (subs != null) {
          for (Subscription sub : subs) {
            if (sub.getId().equalsIgnoreCase(subscriptionId)) {
              return sub;
            }
          }
        }
      }
      return null;
    }

    public void addSubscription(String destination, String subscriptionId, Expression selectorExpression) {
      Set<Subscription> subs = this.destinationLookup.get(destination);
      if (subs == null) {
        synchronized (this.destinationLookup) {
          subs = this.destinationLookup.get(destination);
          if (subs == null) {
            subs = new CopyOnWriteArraySet<Subscription>();
            this.destinationLookup.put(destination, subs);
          }
        }
      }
      subs.add(new Subscription(subscriptionId, selectorExpression));
    }

    public String removeSubscription(String subscriptionId) {
      for (String destination : this.destinationLookup.keySet()) {
        Set<Subscription> subs = this.destinationLookup.get(destination);
        if (subs != null) {
          for (Subscription sub : subs) {
            if (sub.getId().equals(subscriptionId) && subs.remove(sub)) {
              synchronized (this.destinationLookup) {
                if (subs.isEmpty()) {
                  this.destinationLookup.remove(destination);
                }
              }
              return destination;
            }
          }
        }
      }
      return null;
    }

    @Override
    public String toString() {
      return "[sessionId=" + this.sessionId + ", subscriptions=" + this.destinationLookup + "]";
    }
  }

  private static final class Subscription {

    private final String id;

    private final Expression selectorExpression;

    public Subscription(String id, Expression selector) {
      Assert.notNull(id, "Subscription id must not be null");
      this.id = id;
      this.selectorExpression = selector;
    }

    public String getId() {
      return this.id;
    }

    public Expression getSelectorExpression() {
      return this.selectorExpression;
    }

    @Override
    public boolean equals(Object other) {
      return (this == other || (other instanceof Subscription && this.id.equals(((Subscription) other).id)));
    }

    @Override
    public int hashCode() {
      return this.id.hashCode();
    }

    @Override
    public String toString() {
      return "subscription(id=" + this.id + ")";
    }
  }

  private static class SimpMessageHeaderPropertyAccessor implements PropertyAccessor {

    @Override
    public Class<?>[] getSpecificTargetClasses() {
      return new Class<?>[] {MessageHeaders.class};
    }

    @Override
    public boolean canRead(EvaluationContext context, Object target, String name) {
      return true;
    }

    @Override
    public TypedValue read(EvaluationContext context, Object target, String name) throws AccessException {
      MessageHeaders headers = (MessageHeaders) target;
      SimpMessageHeaderAccessor accessor =
          MessageHeaderAccessor.getAccessor(headers, SimpMessageHeaderAccessor.class);
      Object value;
      if ("destination".equalsIgnoreCase(name)) {
        value = accessor.getDestination();
      }
      else {
        value = accessor.getFirstNativeHeader(name);
        if (value == null) {
          value = headers.get(name);
        }
      }
      return new TypedValue(value);
    }

    @Override
    public boolean canWrite(EvaluationContext context, Object target, String name) {
      return false;
    }

    @Override
    public void write(EvaluationContext context, Object target, String name, Object value) {
    }
  }

}

Output:
【漏洞类型】ConcurrentModificationException异常

【严重性】High

【漏洞摘要】此代码存在由于并发修改引起的ConcurrentModificationException异常。具体表现为在DestinationCache类的updateAfterRemovedSubscription和updateAfterRemovedSession方法中，使用了迭代器（iterator）遍历accessCache.entrySet()，同时在遍历过程中对accessCache进行了修改（remove操作），这可能导致ConcurrentModificationException异常。根本原因是这些方法在遍历accessCache时没有使用线程安全的迭代方式，而是直接修改了正在遍历的集合。

【关键代码模式】
- Iterator<Map.Entry<String, LinkedMultiValueMap<String, String>>> iterator = this.accessCache.entrySet().iterator();
- 在遍历过程中调用accessCache.computeIfPresent或accessCache.remove，修改了accessCache。

【修复方法说明】修复方法通过将迭代器的遍历逻辑替换为compute方法的遍历逻辑，确保在遍历accessCache时对集合的修改是线程安全的。同时，避免了在遍历过程中直接修改集合。最佳实践是使用线程安全的集合操作方法，特别是在多线程环境下。


Instruction:
作为 Java 安全专家，检测此代码中的安全漏洞：
## 内容1
### 文件路径：
ambari-server/src/main/java/org/apache/ambari/server/state/alert/MetricSource.java
### 代码内容：
/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.ambari.server.state.alert;

import static java.util.stream.Collectors.toMap;
import static java.util.stream.IntStream.range;

import java.util.List;
import java.util.Objects;
import java.util.Optional;

import org.apache.ambari.server.controller.jmx.JMXMetricHolder;
import org.apache.ambari.server.state.UriInfo;
import org.apache.commons.collections.CollectionUtils;
import org.apache.commons.collections.ListUtils;
import org.springframework.expression.spel.standard.SpelExpressionParser;
import org.springframework.expression.spel.support.StandardEvaluationContext;

import com.fasterxml.jackson.annotation.JsonAutoDetect;
import com.fasterxml.jackson.annotation.JsonInclude;
import com.fasterxml.jackson.annotation.JsonProperty;
import com.google.gson.annotations.SerializedName;

/**
 * Alert when the source type is defined as {@link SourceType#METRIC}
 * <p/>
 * Equality checking for instances of this class should be executed on every
 * member to ensure that reconciling stack differences is correct.
 */
@JsonInclude(JsonInclude.Include.NON_EMPTY)
public class MetricSource extends Source {

  @SerializedName("uri")
  private UriInfo uri = null;

  @SerializedName("jmx")
  private JmxInfo jmxInfo = null;

  @SerializedName("ganglia")
  private String gangliaInfo = null;

  /**
   * @return the jmx info, if this metric is jmx-based
   */
  @JsonProperty("jmx")
  public JmxInfo getJmxInfo() {
    return jmxInfo;
  }

  /**
   * @return the ganglia info, if this metric is ganglia-based
   */
  @JsonProperty("ganglia")
  public String getGangliaInfo() {
    return gangliaInfo;
  }

  /**
   * @return the uri info, which may include port information
   */
  @JsonProperty("uri")
  public UriInfo getUri() {
    return uri;
  }

  @Override
  public int hashCode() {
    return Objects.hash(super.hashCode(), gangliaInfo, uri, jmxInfo);
  }

  @Override
  public boolean equals(Object obj) {
    if (this == obj) {
      return true;
    }

    if (!super.equals(obj)) {
      return false;
    }

    if (getClass() != obj.getClass()) {
      return false;
    }

    MetricSource other = (MetricSource) obj;
    return Objects.equals(gangliaInfo, other.gangliaInfo) &&
      Objects.equals(uri, other.uri) &&
      Objects.equals(jmxInfo, other.jmxInfo);
  }

  /**
   * Represents the {@code jmx} element in a Metric alert.
   */
  @JsonInclude(JsonInclude.Include.NON_EMPTY)
  @JsonAutoDetect(fieldVisibility = JsonAutoDetect.Visibility.ANY, getterVisibility = JsonAutoDetect.Visibility.NONE, setterVisibility = JsonAutoDetect.Visibility.NONE)
  public static class JmxInfo {
    @JsonProperty("property_list")
    @SerializedName("property_list")
    private List<String> propertyList;

    @SerializedName("value")
    private String value = "{0}";

    @JsonProperty("url_suffix")
    @SerializedName("url_suffix")
    private String urlSuffix = "/jmx";

    public List<String> getPropertyList() {
      return propertyList;
    }

    public void setPropertyList(List<String> propertyList) {
      this.propertyList = propertyList;
    }

    public void setValue(String value) {
      this.value = value;
    }

    public Value getValue() {
      return new Value(value);
    }

    @Override
    public boolean equals(Object object) {
      if (object instanceof JmxInfo) {
        JmxInfo other = (JmxInfo) object;
        if (propertyList == null) {
          return other.propertyList == null;
        } else {
          // !!! even if out of order, this is enough to fail
          return other.propertyList != null &&
              CollectionUtils.isEqualCollection(ListUtils.unmodifiableList(propertyList), ListUtils.unmodifiableList(other.propertyList));
        }
      }
      return false;
    }

    @Override
    public int hashCode() {
      return Objects.hash(propertyList);
    }

    public String getUrlSuffix() {
      return urlSuffix;
    }

    public Optional<Number> eval(JMXMetricHolder jmxMetricHolder) {
      List<Object> metrics = jmxMetricHolder.findAll(propertyList);
      if (metrics.isEmpty()) {
        return Optional.empty();
      } else {
        Object value = getValue().eval(metrics);
        return value instanceof Number ? Optional.of((Number)value) : Optional.empty();
      }
    }
  }

  public static class Value {
    private final String value;

    public Value(String value) {
      this.value = value;
    }

    /**
     * Evaluate an expression like "{0}/({0} + {1}) * 100.0" where each positional argument represent a metrics value.
     * The value is converted to SpEL syntax:
     *  #var0/(#var0 + #var1) * 100.0
     * then it is evaluated in the context of the metrics parameters.
     */
    public Object eval(List<Object> metrics) {
      StandardEvaluationContext context = new StandardEvaluationContext();
      context.setVariables(range(0, metrics.size()).boxed().collect(toMap(i -> "var" + i, metrics::get)));
      return new SpelExpressionParser()
        .parseExpression(value.replaceAll("(\\{(\\d+)\\})", "#var$2"))
        .getValue(context);
    }

    @Override
    public String toString() {
      return value;
    }
  }
}