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8207235: ManagementFactory.getPlatformMXBeans(BufferPoolMXBean.class) throws NPE

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Reviewed-by: alanb
This commit is contained in:
Claes Redestad 2018-07-13 18:39:11 +02:00
parent 8afac1c9da
commit 173732afaa
3 changed files with 41 additions and 40 deletions
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55
src/java.base/share/classes/java/nio/Bits.java
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@ -207,43 +207,24 @@ class Bits { // package-private
assert cnt >= 0 && reservedMem >= 0 && totalCap >= 0;
}
// -- Monitoring of direct buffer usage --
static {
// setup access to this package in SharedSecrets
SharedSecrets.setJavaNioAccess(
new JavaNioAccess() {
@Override
public JavaNioAccess.BufferPool getDirectBufferPool() {
return new JavaNioAccess.BufferPool() {
@Override
public String getName() {
return "direct";
}
@Override
public long getCount() {
return Bits.COUNT.get();
}
@Override
public long getTotalCapacity() {
return Bits.TOTAL_CAPACITY.get();
}
@Override
public long getMemoryUsed() {
return Bits.RESERVED_MEMORY.get();
}
};
}
@Override
public ByteBuffer newDirectByteBuffer(long addr, int cap, Object ob) {
return new DirectByteBuffer(addr, cap, ob);
}
@Override
public void truncate(Buffer buf) {
buf.truncate();
}
});
}
static final JavaNioAccess.BufferPool BUFFER_POOL = new JavaNioAccess.BufferPool() {
@Override
public String getName() {
return "direct";
}
@Override
public long getCount() {
return Bits.COUNT.get();
}
@Override
public long getTotalCapacity() {
return Bits.TOTAL_CAPACITY.get();
}
@Override
public long getMemoryUsed() {
return Bits.RESERVED_MEMORY.get();
}
};
// These numbers represent the point at which we have empirically
// determined that the average cost of a JNI call exceeds the expense

21
src/java.base/share/classes/java/nio/Buffer.java
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@ -26,6 +26,8 @@
package java.nio;
import jdk.internal.HotSpotIntrinsicCandidate;
import jdk.internal.misc.JavaNioAccess;
import jdk.internal.misc.SharedSecrets;
import jdk.internal.misc.Unsafe;
import java.util.Spliterator;
@ -707,4 +709,23 @@ public abstract class Buffer {
throw new IndexOutOfBoundsException();
}
static {
// setup access to this package in SharedSecrets
SharedSecrets.setJavaNioAccess(
new JavaNioAccess() {
@Override
public JavaNioAccess.BufferPool getDirectBufferPool() {
return Bits.BUFFER_POOL;
}
@Override
public ByteBuffer newDirectByteBuffer(long addr, int cap, Object ob) {
return new DirectByteBuffer(addr, cap, ob);
}
@Override
public void truncate(Buffer buf) {
buf.truncate();
}
});
}
}

5
src/java.base/share/classes/jdk/internal/misc/SharedSecrets.java
View File

@ -194,10 +194,9 @@ public class SharedSecrets {
public static JavaNioAccess getJavaNioAccess() {
if (javaNioAccess == null) {
// Ensure java.nio.ByteOrder is initialized; we know that
// this class initializes java.nio.Bits that provides the
// Ensure java.nio.Buffer is initialized, which provides the
// shared secret.
unsafe.ensureClassInitialized(java.nio.ByteOrder.class);
unsafe.ensureClassInitialized(java.nio.Buffer.class);
}
return javaNioAccess;
}