[bugfix](jvmmetrics) some object is nullptr if java support is not enabled

[yiguolei]

What problem does this PR solve?

Issue Number: close #xxx

Related PR: #xxx

Problem Summary:

Release note

None

Check List (For Author)

• Test

  • Regression test
  • Unit Test
  • Manual test (add detailed scripts or steps below)
  • No need to test or manual test. Explain why:
    • This is a refactor/code format and no logic has been changed.
    • Previous test can cover this change.
    • No code files have been changed.
    • Other reason

• Behavior changed:

  • No.
  • Yes.

• Does this need documentation?

  • No.
  • Yes.

Check List (For Reviewer who merge this PR)

• Confirm the release note
• Confirm test cases
• Confirm document
• Add branch pick label

[Thearas]

Thank you for your contribution to Apache Doris.
Don't know what should be done next? See How to process your PR.

Please clearly describe your PR:

1. What problem was fixed (it's best to include specific error reporting information). How it was fixed.
2. Which behaviors were modified. What was the previous behavior, what is it now, why was it modified, and what possible impacts might there be.
3. What features were added. Why was this function added?
4. Which code was refactored and why was this part of the code refactored?
5. Which functions were optimized and what is the difference before and after the optimization?

[yiguolei]

run buildall

[doris-robot]

TPC-H: Total hot run time: 35932 ms

machine: 'aliyun_ecs.c7a.8xlarge_32C64G'
scripts: https://github.com/apache/doris/tree/master/tools/tpch-tools
Tpch sf100 test result on commit 1c0efb7ec3e1a0bbfcf64abcf708616b1f4cec13, data reload: false

------ Round 1 ----------------------------------
q1	17613	5284	5071	5071
q2	2036	350	213	213
q3	10190	1300	728	728
q4	10226	878	360	360
q5	7451	2366	2364	2364
q6	184	173	140	140
q7	910	779	633	633
q8	9375	1345	1149	1149
q9	6940	5181	5151	5151
q10	6880	2242	1840	1840
q11	516	294	289	289
q12	336	363	240	240
q13	17765	3639	3036	3036
q14	246	232	217	217
q15	572	525	525	525
q16	1046	1011	966	966
q17	578	863	364	364
q18	7716	7541	8035	7541
q19	1241	942	577	577
q20	372	366	239	239
q21	4576	3503	3213	3213
q22	1122	1124	1076	1076
Total cold run time: 107891 ms
Total hot run time: 35932 ms

----- Round 2, with runtime_filter_mode=off -----
q1	5385	5296	5386	5296
q2	251	332	230	230
q3	2411	2965	2451	2451
q4	1498	1971	1456	1456
q5	4642	4522	4401	4401
q6	217	164	126	126
q7	2124	1981	1798	1798
q8	2699	2675	2556	2556
q9	7310	7350	7185	7185
q10	3055	3234	2859	2859
q11	582	510	497	497
q12	650	728	608	608
q13	3302	3650	3069	3069
q14	268	278	258	258
q15	534	489	484	484
q16	1022	1050	1004	1004
q17	1119	1521	1331	1331
q18	7400	7206	7026	7026
q19	759	807	898	807
q20	1918	1964	1811	1811
q21	4765	4471	4301	4301
q22	1096	1048	985	985
Total cold run time: 53007 ms
Total hot run time: 50539 ms

[doris-robot]

TPC-DS: Total hot run time: 188188 ms

machine: 'aliyun_ecs.c7a.8xlarge_32C64G'
scripts: https://github.com/apache/doris/tree/master/tools/tpcds-tools
TPC-DS sf100 test result on commit 1c0efb7ec3e1a0bbfcf64abcf708616b1f4cec13, data reload: false

query1	1038	409	389	389
query2	6562	1731	1703	1703
query3	6756	224	224	224
query4	26585	23385	23427	23385
query5	4424	634	491	491
query6	353	253	244	244
query7	4660	514	309	309
query8	312	254	255	254
query9	8707	2628	2634	2628
query10	506	347	296	296
query11	15383	15456	14771	14771
query12	193	131	116	116
query13	1691	585	452	452
query14	11436	9319	9222	9222
query15	204	187	173	173
query16	7682	696	529	529
query17	1214	751	617	617
query18	2028	419	315	315
query19	209	201	186	186
query20	132	128	124	124
query21	220	132	112	112
query22	3962	4101	4026	4026
query23	33953	32838	33098	32838
query24	8457	2411	2359	2359
query25	587	512	456	456
query26	1242	280	164	164
query27	2724	496	357	357
query28	4425	2238	2200	2200
query29	760	612	488	488
query30	306	228	196	196
query31	905	812	761	761
query32	83	73	73	73
query33	585	384	341	341
query34	797	845	534	534
query35	817	832	721	721
query36	949	996	892	892
query37	124	108	90	90
query38	3571	3503	3465	3465
query39	1483	1431	1390	1390
query40	223	130	115	115
query41	62	60	63	60
query42	130	114	114	114
query43	499	511	481	481
query44	1221	766	752	752
query45	186	174	177	174
query46	882	992	631	631
query47	1763	1805	1737	1737
query48	389	429	326	326
query49	784	530	431	431
query50	640	675	421	421
query51	3880	3978	3920	3920
query52	115	113	102	102
query53	241	263	192	192
query54	309	298	316	298
query55	90	86	87	86
query56	318	337	309	309
query57	1177	1165	1132	1132
query58	282	294	269	269
query59	2610	2746	2567	2567
query60	370	348	344	344
query61	172	153	162	153
query62	804	709	661	661
query63	230	194	199	194
query64	4460	1153	856	856
query65	4052	3918	3932	3918
query66	1113	436	348	348
query67	15265	15190	14958	14958
query68	3885	903	610	610
query69	488	322	282	282
query70	1384	1317	1286	1286
query71	428	335	314	314
query72	6171	5200	5090	5090
query73	629	583	363	363
query74	9133	9179	8815	8815
query75	3327	3359	2863	2863
query76	3304	1151	738	738
query77	495	398	335	335
query78	9519	9743	8839	8839
query79	2349	835	595	595
query80	1646	586	508	508
query81	591	263	225	225
query82	400	166	134	134
query83	360	263	245	245
query84	259	110	98	98
query85	922	489	459	459
query86	466	313	297	297
query87	3745	3732	3641	3641
query88	2900	2294	2256	2256
query89	392	329	298	298
query90	1916	230	228	228
query91	188	166	138	138
query92	86	71	66	66
query93	2504	960	642	642
query94	771	456	347	347
query95	424	320	310	310
query96	479	583	287	287
query97	2926	2965	2907	2907
query98	237	213	205	205
query99	1328	1441	1327	1327
Total cold run time: 271944 ms
Total hot run time: 188188 ms

[doris-robot]

ClickBench: Total hot run time: 27.49 s

machine: 'aliyun_ecs.c7a.8xlarge_32C64G'
scripts: https://github.com/apache/doris/tree/master/tools/clickbench-tools
ClickBench test result on commit 1c0efb7ec3e1a0bbfcf64abcf708616b1f4cec13, data reload: false

query1	0.05	0.05	0.05
query2	0.10	0.05	0.04
query3	0.26	0.09	0.08
query4	1.61	0.12	0.11
query5	0.27	0.25	0.25
query6	1.19	0.66	0.65
query7	0.03	0.02	0.02
query8	0.06	0.04	0.04
query9	0.59	0.54	0.52
query10	0.58	0.58	0.58
query11	0.17	0.11	0.11
query12	0.15	0.12	0.12
query13	0.64	0.61	0.61
query14	1.01	0.99	1.01
query15	0.86	0.83	0.85
query16	0.40	0.39	0.39
query17	1.02	1.01	1.03
query18	0.21	0.21	0.19
query19	1.92	1.81	1.78
query20	0.02	0.01	0.01
query21	15.44	0.20	0.13
query22	5.07	0.07	0.05
query23	15.68	0.26	0.11
query24	2.75	1.46	0.37
query25	0.09	0.07	0.06
query26	0.14	0.13	0.13
query27	0.08	0.07	0.05
query28	5.34	1.14	0.93
query29	12.66	3.90	3.31
query30	0.30	0.15	0.12
query31	2.82	0.60	0.38
query32	3.23	0.57	0.47
query33	3.09	3.02	3.07
query34	15.93	5.12	4.55
query35	4.57	4.61	4.56
query36	0.66	0.50	0.52
query37	0.11	0.07	0.07
query38	0.07	0.04	0.04
query39	0.03	0.03	0.04
query40	0.18	0.15	0.14
query41	0.09	0.03	0.03
query42	0.04	0.03	0.03
query43	0.04	0.03	0.04
Total cold run time: 99.55 s
Total hot run time: 27.49 s

[doris-robot]

BE UT Coverage Report

Increment line coverage 0.00% (0/12) 🎉

Increment coverage report
Complete coverage report

Category	Coverage
Function Coverage	52.81% (18279/34611)
Line Coverage	38.17% (166155/435267)
Region Coverage	33.18% (129214/389458)
Branch Coverage	33.91% (55436/163495)

[hello-stephen]

BE Regression && UT Coverage Report

Increment line coverage 100.00% (12/12) 🎉

Increment coverage report
Complete coverage report

Category	Coverage
Function Coverage	71.54% (24331/34011)
Line Coverage	58.01% (252888/435943)
Region Coverage	53.39% (210857/394969)
Branch Coverage	54.68% (89992/164570)

[zclllyybb]

LGTM

[github-actions]

PR approved by at least one committer and no changes requested.

[github-actions]

PR approved by anyone and no changes requested.

[hubgeter]

LGTM