2 added 1 character in body
source | link

J - 444 bytes

I liked the number, so stopped golfing. Here 'ya go, single expression function!

f=:'Source code contains invalid characters'"_`('Hello, world!'"_`[`((((s=:(<:@[s],L,(v,LF,'Take one down and pass it around, '"_,b@<:,' of beer on the wall.'"_)@[,''"_)`(],(L=:LF,LF),(v=:1&b,' of beer on the wall, '"_,b,' of beer.'"_)@[)@.([<1:))''"_),LF,'Go to the store and buy some more, '"_,(b=:({&'Nn'@([=0:),'o more'"_)`(":@])@.(]>0:),{.&' bottles'@(8:-=&1@])),' of beer on the wall.'"_)@(99"_))`]@.('HQ9+'&i.@])"0 1 0])@.(*./@e.&'HQ9+')

Examples:

   hq9 '9QHHQ+'
99 bottles of beer on the wall, 99 bottles of beer.
Take one down and pass it around, 98 bottles of beer on the wall.

98 bottles of beer on the wall, 98 bottles of beer.
Take one down and pass it around, 97 bottles of beer on the wall.

...

3 bottles of beer on the wall, 3 bottles of beer.
Take one down and pass it around, 2 bottles of beer on the wall.

2 bottles of beer on the wall, 2 bottles of beer.
Take one down and pass it around, 1 bottle of beer on the wall.

1 bottle of beer on the wall, 1 bottle of beer.
Take one down and pass it around, no more bottles of beer on the wall.

No more bottles of beer on the wall, no more bottles of beer.
Go to the store and buy some more, 99 bottles of beer on the wall.
9QHHQ+
Hello, world!
Hello, world!
9QHHQ+
+
   hq9 '9QHHaQ'
Source code contains invalid characters

J - 444 bytes

I liked the number, so stopped golfing. Here 'ya go, single expression function!

f=:'Source code contains invalid characters'"_`('Hello, world!'"_`[`((((s=:(<:@[s],L,(v,LF,'Take one down and pass it around, '"_,b@<:,' of beer on the wall.'"_)@[,''"_)`(],(L=:LF,LF),(v=:1&b,' of beer on the wall, '"_,b,' of beer.'"_)@[)@.([<1:))''"_),LF,'Go to the store and buy some more, '"_,(b=:({&'Nn'@([=0:),'o more'"_)`(":@])@.(]>0:),{.&' bottles'@(8:-=&1@])),' of beer on the wall.'"_)@(99"_))`]@.('HQ9+'&i.@])"0 1 0])@.(*./@e.&'HQ9+')

Examples:

   hq9 '9QHHQ+'
99 bottles of beer on the wall, 99 bottles of beer.
Take one down and pass it around, 98 bottles of beer on the wall.

98 bottles of beer on the wall, 98 bottles of beer.
Take one down and pass it around, 97 bottles of beer on the wall.

...

3 bottles of beer on the wall, 3 bottles of beer.
Take one down and pass it around, 2 bottles of beer on the wall.

2 bottles of beer on the wall, 2 bottles of beer.
Take one down and pass it around, 1 bottle of beer on the wall.

1 bottle of beer on the wall, 1 bottle of beer.
Take one down and pass it around, no more bottles of beer on the wall.

No more bottles of beer on the wall, no more bottles of beer.
Go to the store and buy some more, 99 bottles of beer on the wall.
9QHHQ+
Hello, world!
Hello, world!
9QHHQ+
+
   hq9 '9QHHaQ'
Source code contains invalid characters

J - 444 bytes

I liked the number, so stopped golfing. Here 'ya go, single expression function!

f=:'Source code contains invalid characters'"_`('Hello, world!'"_`[`((((s=:(<:@[s],L,(v,LF,'Take one down and pass it around, '"_,b@<:,' of beer on the wall.'"_)@[,''"_)`(],(L=:LF,LF),(v=:1&b,' of beer on the wall, '"_,b,' of beer.'"_)@[)@.([<1:))''"_),LF,'Go to the store and buy some more, '"_,(b=:({&'Nn'@([=0:),'o more'"_)`(":@])@.(]>0:),{.&' bottles'@(8:-=&1@])),' of beer on the wall.'"_)@(99"_))`]@.('HQ9+'&i.@])"0 1 0])@.(*./@e.&'HQ9+')

Examples:

   hq9 '9QHHQ+'
99 bottles of beer on the wall, 99 bottles of beer.
Take one down and pass it around, 98 bottles of beer on the wall.

98 bottles of beer on the wall, 98 bottles of beer.
Take one down and pass it around, 97 bottles of beer on the wall.

...

3 bottles of beer on the wall, 3 bottles of beer.
Take one down and pass it around, 2 bottles of beer on the wall.

2 bottles of beer on the wall, 2 bottles of beer.
Take one down and pass it around, 1 bottle of beer on the wall.

1 bottle of beer on the wall, 1 bottle of beer.
Take one down and pass it around, no more bottles of beer on the wall.

No more bottles of beer on the wall, no more bottles of beer.
Go to the store and buy some more, 99 bottles of beer on the wall.
9QHHQ+
Hello, world!
Hello, world!
9QHHQ+
+
   hq9 '9QHHaQ'
Source code contains invalid characters
1
source | link

J - 444 bytes

I liked the number, so stopped golfing. Here 'ya go, single expression function!

f=:'Source code contains invalid characters'"_`('Hello, world!'"_`[`((((s=:(<:@[s],L,(v,LF,'Take one down and pass it around, '"_,b@<:,' of beer on the wall.'"_)@[,''"_)`(],(L=:LF,LF),(v=:1&b,' of beer on the wall, '"_,b,' of beer.'"_)@[)@.([<1:))''"_),LF,'Go to the store and buy some more, '"_,(b=:({&'Nn'@([=0:),'o more'"_)`(":@])@.(]>0:),{.&' bottles'@(8:-=&1@])),' of beer on the wall.'"_)@(99"_))`]@.('HQ9+'&i.@])"0 1 0])@.(*./@e.&'HQ9+')

Examples:

   hq9 '9QHHQ+'
99 bottles of beer on the wall, 99 bottles of beer.
Take one down and pass it around, 98 bottles of beer on the wall.

98 bottles of beer on the wall, 98 bottles of beer.
Take one down and pass it around, 97 bottles of beer on the wall.

...

3 bottles of beer on the wall, 3 bottles of beer.
Take one down and pass it around, 2 bottles of beer on the wall.

2 bottles of beer on the wall, 2 bottles of beer.
Take one down and pass it around, 1 bottle of beer on the wall.

1 bottle of beer on the wall, 1 bottle of beer.
Take one down and pass it around, no more bottles of beer on the wall.

No more bottles of beer on the wall, no more bottles of beer.
Go to the store and buy some more, 99 bottles of beer on the wall.
9QHHQ+
Hello, world!
Hello, world!
9QHHQ+
+
   hq9 '9QHHaQ'
Source code contains invalid characters