diff --git a/src/afs/VNOPS/afs_vnop_flock.c b/src/afs/VNOPS/afs_vnop_flock.c
index e2eaf8ac67..af942f18fc 100644
--- a/src/afs/VNOPS/afs_vnop_flock.c
+++ b/src/afs/VNOPS/afs_vnop_flock.c
@@ -547,6 +547,10 @@ int afs_lockctl(struct vcache * avc, struct AFS_FLOCK * af, int acmd,
 	af->l_len = 0;		/* since some systems indicate it as EOF */
 #endif
 #endif
+    /* Java VMs ask for l_len=(long)-1 regardless of OS/CPU; bottom 32 bits
+     * sometimes get masked off by OS */
+    if ((af->l_len >> 32) == 0x7fffffff)
+	af->l_len = 0;
     /* next line makes byte range locks always succeed,
      * even when they should block */
     if (af->l_whence != 0 || af->l_start != 0 || af->l_len != 0) {