小编fuy*_*001的帖子

我在我的程序上运行了一个堆转储.当我在内存分析器工具中打开它时,我发现java.lang.ref.Finalizerfor org.logicalcobwebs.proxool.ProxyStatement占用了大量内存.为什么会这样？

异常堆栈是

java.nio.BufferOverflowException
     at java.nio.DirectByteBuffer.put(DirectByteBuffer.java:327)
     at java.nio.ByteBuffer.put(ByteBuffer.java:813)
            mappedByteBuffer.put(bytes);

代码:

randomAccessFile = new RandomAccessFile(file, "rw");
fileChannel = randomAccessFile.getChannel();
mappedByteBuffer = fileChannel.map(MapMode.READ_WRITE, 0, file.length());

并打电话 mappedByteBuffer.put(bytes);

是什么原因 mappedByteBuffer.put(bytes)抛出BufferOverflowException
如何查找原因？

Map<String,Object> map = Maps.newHashMap();
map.put("test","123");
map.put("fuyou001","456");
map.put("id",145);
List<Map<String,Object>> list = Lists.newArrayList();
list.add(map);
Lists.transform(list, new Function<Map<String, Object>, Object>() {
  @Override
  public Object apply(@Nullable Map<String, Object> input) {
    System.out.println("test:" + input);
    return input;
  }
});
System.out.println(list);`

控制台不显示"test ...."

如何避免懒惰应用
我也试试

List<Map<String,Object>> newList = new ArrayList<Map<String, Object>>(list.size());
Collections.copy(newList,list);

但没有效果

在阅读源代码时ArrayBlockingQueue,我发现了一条评论,说明它使用了" 任何教科书中的经典双条件算法 ":

/*
 * Concurrency control uses the classic two-condition algorithm
 * found in any textbook.
 */

/** Main lock guarding all access */
private final ReentrantLock lock;
/** Condition for waiting takes */
private final Condition notEmpty;
/** Condition for waiting puts */
private final Condition notFull;

为什么它使用经典的双条件(notEmpty,notFull)算法？

在一个Web项目中。
我看到日志：

hadoop.hbase.zookeeper.ZKConfig - java.net.UnknownHostException: example.com 
at java.net.Inet6AddressImpl.lookupAllHostAddr(Native Method)
at java.net.InetAddress$1.lookupAllHostAddr(InetAddress.java:850)
at java.net.InetAddress.getAddressFromNameService(InetAddress.java:1201)
at java.net.InetAddress.getAllByName0(InetAddress.java:1154)
at java.net.InetAddress.getAllByName(InetAddress.java:1084)
at java.net.InetAddress.getAllByName(InetAddress.java:1020)
at java.net.InetAddress.getByName(InetAddress.java:970)

但是当我ping example.com时，没关系，我也成功telnet example.com 2181！我发现了类似的问题， 所以我在服务器Java DomainResolutionTest example.com中 运行DomainResolutionTest，
但是没关系！

环境：

java -version

Java版本“ 1.6.0_25”
Java™SE运行时环境（内部版本1.6.0_25-b06）
Java HotSpot（TM）64位服务器VM（内部版本20.0-b11，混合模式）

os:Red Hat Enterprise Linux Server release 5.7

我很好奇为什么是Inet6AddressImpl，我想可能是Inet4AddressImpl

怎么解决呢？
是什么原因？

我发生锁定等待超时超出错误。以下是例外：

org.springframework.dao.CannotAcquireLockException: 
### Error updating database.  Cause: java.sql.SQLException: Lock wait timeout exceeded; try restarting transaction
### The error may involve commManager.updateOrderHotelInfo-Inline
### The error occurred while setting parameters
### Cause: java.sql.SQLException: Lock wait timeout exceeded; try restarting transaction
; SQL []; Lock wait timeout exceeded; try restarting transaction; nested exception is java.sql.SQLException: Lock wait timeout exceeded; try restarting transaction
 at org.springframework.jdbc.support.SQLErrorCodeSQLExceptionTranslator.doTranslate(SQLErrorCodeSQLExceptionTranslator.java:261)
 at org.springframework.jdbc.support.AbstractFallbackSQLExceptionTranslator.translate(AbstractFallbackSQLExceptionTranslator.java:72)
 at org.mybatis.spring.MyBatisExceptionTranslator.translateExceptionIfPossible(MyBatisExceptionTranslator.java:71)
 at org.mybatis.spring.SqlSessionTemplate$SqlSessionInterceptor.invoke(SqlSessionTemplate.java:358)
 at $Proxy21.update(Unknown Source)
 at org.mybatis.spring.SqlSessionTemplate.update(SqlSessionTemplate.java:246)

春季交易配置 <bean id="transactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager"> <property name="dataSource" ref="dataSource" /> …