openjdk has been removed but I am seeing something similar with openjdk to, so reopened + reassigned.
With 10 installed: $ ./Minecraft.jar invalid file (bad magic number): Exec format error $ /usr/lib/jvm/java-10-openjdk-amd64/lib/jexec Minecraft.jar invalid file (bad magic number): Exec format error $ sudo update-alternatives --display java java - auto mode link best version is /usr/lib/jvm/java-10-openjdk-amd64/bin/java link currently points to /usr/lib/jvm/java-10-openjdk-amd64/bin/java link java is /usr/bin/java slave java.1.gz is /usr/share/man/man1/java.1.gz /usr/lib/jvm/java-10-openjdk-amd64/bin/java - priority 1101 slave java.1.gz: /usr/lib/jvm/java-10-openjdk-amd64/man/man1/java.1.gz /usr/lib/jvm/java-8-openjdk-amd64/jre/bin/java - priority 1081 slave java.1.gz: /usr/lib/jvm/java-8-openjdk-amd64/jre/man/man1/java.1.gz $ sudo update-alternatives --display jexec jexec - auto mode link best version is /usr/lib/jvm/java-10-openjdk-amd64/lib/jexec link currently points to /usr/lib/jvm/java-10-openjdk-amd64/lib/jexec link jexec is /usr/bin/jexec slave jexec-binfmt is /usr/share/binfmts/jar /usr/lib/jvm/java-10-openjdk-amd64/lib/jexec - priority 1101 slave jexec-binfmt: /usr/lib/jvm/java-10-openjdk-amd64/lib/jar.binfmt /usr/lib/jvm/java-8-openjdk-amd64/jre/lib/jexec - priority 1081 slave jexec-binfmt: /usr/lib/jvm/java-8-openjdk-amd64/jre/lib/jar.binfmt $ dpkg -l "openjdk*" Desired=Unknown/Install/Remove/Purge/Hold | Status=Not/Inst/Conf-files/Unpacked/halF-conf/Half-inst/trig-aWait/Trig-pend |/ Err?=(none)/Reinst-required (Status,Err: uppercase=bad) ||/ Name Version Architecture Description +++-=======================-================-================-==================================================== un openjdk-10-demo <none> <none> (no description available) ii openjdk-10-jdk:amd64 10.0.1+10-4 amd64 OpenJDK Development Kit (JDK) ii openjdk-10-jdk-headless 10.0.1+10-4 amd64 OpenJDK Development Kit (JDK) (headless) ii openjdk-10-jre:amd64 10.0.1+10-4 amd64 OpenJDK Java runtime, using Hotspot JIT ii openjdk-10-jre-headless 10.0.1+10-4 amd64 OpenJDK Java runtime, using Hotspot JIT (headless) un openjdk-10-source <none> <none> (no description available) un openjdk-6-jre <none> <none> (no description available) un openjdk-6-jre-headless <none> <none> (no description available) in openjdk-7-jre-lib <none> all (no description available) un openjdk-8-demo <none> <none> (no description available) ii openjdk-8-jdk:amd64 8u162-b12-1 amd64 OpenJDK Development Kit (JDK) ii openjdk-8-jdk-headless: 8u162-b12-1 amd64 OpenJDK Development Kit (JDK) (headless) ii openjdk-8-jre:amd64 8u162-b12-1 amd64 OpenJDK Java runtime, using Hotspot JIT ii openjdk-8-jre-headless: 8u162-b12-1 amd64 OpenJDK Java runtime, using Hotspot JIT (headless) un openjdk-8-source <none> <none> (no description available) rc openjdk-9-jre-headless: 9.0.4+12-2 amd64 OpenJDK Java runtime, using Hotspot JIT (headless) $ strace -fff /usr/lib/jvm/java-10-openjdk-amd64/lib/jexec ./Minecraft.jar execve("/usr/lib/jvm/java-10-openjdk-amd64/lib/jexec", ["/usr/lib/jvm/java-10-openjdk-amd"..., "./Minecraft.jar"], 0x7ffd79d3e760 /* 52 vars */) = 0 brk(NULL) = 0x55b7b57f4000 access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory) access("/etc/ld.so.preload", R_OK) = -1 ENOENT (No such file or directory) openat(AT_FDCWD, "/etc/ld.so.cache", O_RDONLY|O_CLOEXEC) = 3 fstat(3, {st_mode=S_IFREG|0644, st_size=280250, ...}) = 0 mmap(NULL, 280250, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7f01c424c000 close(3) = 0 access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory) openat(AT_FDCWD, "/lib/x86_64-linux-gnu/libc.so.6", O_RDONLY|O_CLOEXEC) = 3 read(3, "\177ELF\2\1\1\3\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0\240\33\2\0\0\0\0\0"..., 832) = 832 fstat(3, {st_mode=S_IFREG|0755, st_size=1800248, ...}) = 0 mmap(NULL, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f01c424a000 mmap(NULL, 3906368, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7f01c3cb3000 mprotect(0x7f01c3e64000, 2093056, PROT_NONE) = 0 mmap(0x7f01c4063000, 24576, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x1b0000) = 0x7f01c4063000 mmap(0x7f01c4069000, 15168, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x7f01c4069000 close(3) = 0 arch_prctl(ARCH_SET_FS, 0x7f01c424b500) = 0 mprotect(0x7f01c4063000, 16384, PROT_READ) = 0 mprotect(0x55b7b43af000, 4096, PROT_READ) = 0 mprotect(0x7f01c4291000, 4096, PROT_READ) = 0 munmap(0x7f01c424c000, 280250) = 0 lstat("/usr", {st_mode=S_IFDIR|0755, st_size=4096, ...}) = 0 lstat("/usr/lib", {st_mode=S_IFDIR|0755, st_size=73728, ...}) = 0 lstat("/usr/lib/jvm", {st_mode=S_IFDIR|0755, st_size=4096, ...}) = 0 lstat("/usr/lib/jvm/java-10-openjdk-amd64", {st_mode=S_IFDIR|0755, st_size=4096, ...}) = 0 lstat("/usr/lib/jvm/java-10-openjdk-amd64/lib", {st_mode=S_IFDIR|0755, st_size=4096, ...}) = 0 lstat("/usr/lib/jvm/java-10-openjdk-amd64/lib/jexec", {st_mode=S_IFREG|0755, st_size=10480, ...}) = 0 brk(NULL) = 0x55b7b57f4000 brk(0x55b7b5815000) = 0x55b7b5815000 getcwd("/local/scratch/ijc/Games", 4096) = 25 lstat("/local/scratch/ijc/Games/Minecraft.jar", {st_mode=S_IFREG|0755, st_size=280212, ...}) = 0 openat(AT_FDCWD, "/local/scratch/ijc/Games/Minecraft.jar", O_RDONLY) = 3 read(3, "PK\3\4\n\0\0\10\10\0\222t\354B\0\0\0\0\2\0\0\0\0\0\0\0\t\0\0\0ME"..., 65535) = 65535 close(3) = 0 dup(2) = 3 fcntl(3, F_GETFL) = 0x8002 (flags O_RDWR|O_LARGEFILE) fstat(3, {st_mode=S_IFCHR|0620, st_rdev=makedev(136, 14), ...}) = 0 write(3, "invalid file (bad magic number):"..., 51invalid file (bad magic number): Exec format error ) = 51 close(3) = 0 exit_group(1) = ? +++ exited with 1 +++ Thanks, Ian.