diff -Nru coco-java-20110419/debian/changelog coco-java-20110419/debian/changelog
--- coco-java-20110419/debian/changelog	2023-08-07 05:15:04.000000000 +1200
+++ coco-java-20110419/debian/changelog	2023-11-22 10:42:13.000000000 +1300
@@ -1,3 +1,11 @@
+coco-java (20110419-5) UNRELEASED; urgency=medium
+
+  * d/p/debian.patch, d/rules: use java_compat_level variable provided
+    by java-common to adjust -source/-target level to the minimum
+    required by the default Java (Closes: #1053019).
+
+ -- Vladimir Petko <vladimir.petko@canonical.com>  Wed, 22 Nov 2023 10:42:13 +1300
+
 coco-java (20110419-4) unstable; urgency=medium
 
   * QA upload.
diff -Nru coco-java-20110419/debian/patches/debian.patch coco-java-20110419/debian/patches/debian.patch
--- coco-java-20110419/debian/patches/debian.patch	2023-08-07 05:15:04.000000000 +1200
+++ coco-java-20110419/debian/patches/debian.patch	2023-11-22 10:42:13.000000000 +1300
@@ -2,7 +2,7 @@
 +++ coco-java-20110419/Makefile
 @@ -0,0 +1,13 @@
 +all:
-+	javac -d . -source 1.7 -target 1.7 Trace.java Scanner.java Tab.java DFA.java ParserGen.java Parser.java Coco.java
++	javac -d . -source $$JAVA_COMPAT_LEVEL -target $$JAVA_COMPAT_LEVEL Trace.java Scanner.java Tab.java DFA.java ParserGen.java Parser.java Coco.java
 +	jar cfm Coco.jar Coco.manifest Coco/*.class
 +	rm -rf Coco
 +
diff -Nru coco-java-20110419/debian/rules coco-java-20110419/debian/rules
--- coco-java-20110419/debian/rules	2023-08-07 05:15:04.000000000 +1200
+++ coco-java-20110419/debian/rules	2023-11-22 10:42:13.000000000 +1300
@@ -9,8 +9,8 @@
 # Uncomment this to turn on verbose mode.
 #export DH_VERBOSE=1
 
-
-
+include /usr/share/java/java_defaults.mk
+export JAVA_COMPAT_LEVEL=$(java_compat_level)
 
 CFLAGS = -Wall -g