8069269: (spec) Defect in the System.nanoTime spec
Summary: Change the description of how to compare two nanoTime values.
Reviewed-by: martin
--- a/jdk/src/java.base/share/classes/java/lang/System.java Mon Jan 26 17:26:49 2015 +0000
+++ b/jdk/src/java.base/share/classes/java/lang/System.java Mon Jan 26 17:16:57 2015 -0800
@@ -376,19 +376,16 @@
* the difference between two such values, obtained within the same
* instance of a Java virtual machine, is computed.
*
- * <p> For example, to measure how long some code takes to execute:
- * <pre> {@code
+ * <p>For example, to measure how long some code takes to execute:
+ * <pre> {@code
* long startTime = System.nanoTime();
* // ... the code being measured ...
- * long estimatedTime = System.nanoTime() - startTime;}</pre>
+ * long elapsedNanos = System.nanoTime() - startTime;}</pre>
*
- * <p>To compare two nanoTime values
- * <pre> {@code
- * long t0 = System.nanoTime();
- * ...
- * long t1 = System.nanoTime();}</pre>
- *
- * one should use {@code t1 - t0 < 0}, not {@code t1 < t0},
+ * <p>To compare elapsed time against a timeout, use <pre> {@code
+ * if (System.nanoTime() - startTime >= timeoutNanos) ...}</pre>
+ * instead of <pre> {@code
+ * if (System.nanoTime() >= startTime + timeoutNanos) ...}</pre>
* because of the possibility of numerical overflow.
*
* @return the current value of the running Java Virtual Machine's